summaryrefslogtreecommitdiff
path: root/apt-pkg/contrib/fileutl.cc
blob: f3c7b6d3bf498cdc9e854572407a743662982f30 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
// -*- mode: cpp; mode: fold -*-
// Description								/*{{{*/
/* ######################################################################
   
   File Utilities
   
   CopyFile - Buffered copy of a single file
   GetLock - dpkg compatible lock file manipulation (fcntl)
   
   Most of this source is placed in the Public Domain, do with it what 
   you will
   It was originally written by Jason Gunthorpe <jgg@debian.org>.
   FileFd gzip support added by Martin Pitt <martin.pitt@canonical.com>
   
   The exception is RunScripts() it is under the GPLv2

   ##################################################################### */
									/*}}}*/
// Include Files							/*{{{*/
#include <config.h>

#include <apt-pkg/fileutl.h>
#include <apt-pkg/strutl.h>
#include <apt-pkg/error.h>
#include <apt-pkg/sptr.h>
#include <apt-pkg/aptconfiguration.h>
#include <apt-pkg/configuration.h>
#include <apt-pkg/macros.h>
#include <apt-pkg/endian.h>

#include <ctype.h>
#include <stdarg.h>
#include <stddef.h>
#include <sys/select.h>
#include <time.h>
#include <string>
#include <vector>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <iostream>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <dirent.h>
#include <signal.h>
#include <errno.h>
#include <glob.h>
#include <pwd.h>
#include <grp.h>

#include <set>
#include <algorithm>
#include <memory>

#ifdef HAVE_ZLIB
	#include <zlib.h>
#endif
#ifdef HAVE_BZ2
	#include <bzlib.h>
#endif
#ifdef HAVE_LZMA
	#include <lzma.h>
#endif
#ifdef HAVE_LZ4
	#include <lz4frame.h>
#endif
#include <endian.h>
#include <stdint.h>

#if __gnu_linux__
#include <sys/prctl.h>
#endif

#include <apti18n.h>

//posix spawn
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <spawn.h>
#include <sys/wait.h>

									/*}}}*/

using namespace std;

/* Should be a multiple of the common page size (4096) */
static constexpr unsigned long long APT_BUFFER_SIZE = 64 * 1024;

extern char **environ;

// RunScripts - Run a set of scripts from a configuration subtree	/*{{{*/
// ---------------------------------------------------------------------
/* */
bool RunScripts(const char *Cnf)
{
   Configuration::Item const *Opts = _config->Tree(Cnf);
   if (Opts == 0 || Opts->Child == 0)
      return true;
   Opts = Opts->Child;

   // Fork for running the system calls
   pid_t Child = ExecFork();
   
   // This is the child
   if (Child == 0)
   {
      if (_config->FindDir("DPkg::Chroot-Directory","/") != "/") 
      {
         std::cerr << "Chrooting into " 
                   << _config->FindDir("DPkg::Chroot-Directory") 
                   << std::endl;
         if (chroot(_config->FindDir("DPkg::Chroot-Directory","/").c_str()) != 0)
            _exit(100);
      }

      if (chdir("/tmp/") != 0)
	 _exit(100);
	 
      unsigned int Count = 1;
      for (; Opts != 0; Opts = Opts->Next, Count++)
      {
	 if (Opts->Value.empty() == true)
	    continue;

         if(_config->FindB("Debug::RunScripts", false) == true)
            std::clog << "Running external script: '"
                      << Opts->Value << "'" << std::endl;

	 if (RunCmd(Opts->Value.c_str()) != 0)
	    _exit(100+Count);
      }
      _exit(0);
   }      

   // Wait for the child
   int Status = 0;
   while (waitpid(Child,&Status,0) != Child)
   {
      if (errno == EINTR)
	 continue;
      return _error->Errno("waitpid","Couldn't wait for subprocess");
   }

   // Restore sig int/quit
   signal(SIGQUIT,SIG_DFL);
   signal(SIGINT,SIG_DFL);   

   // Check for an error code.
   if (WIFEXITED(Status) == 0 || WEXITSTATUS(Status) != 0)
   {
      unsigned int Count = WEXITSTATUS(Status);
      if (Count > 100)
      {
	 Count -= 100;
	 for (; Opts != 0 && Count != 1; Opts = Opts->Next, Count--);
	 _error->Error("Problem executing scripts %s '%s'",Cnf,Opts->Value.c_str());
      }
      
      return _error->Error("Sub-process returned an error code");
   }
   
   return true;
}

#define PROC_PIDPATHINFO_MAXSIZE  (1024)
static int file_exist(const char *filename) {
    struct stat buffer;
    int r = stat(filename, &buffer);
    return (r == 0);
}

static char *searchpath(const char *binaryname){
    if (strstr(binaryname, "/") != NULL){
        if (file_exist(binaryname)){
            char *foundpath = (char *)malloc((strlen(binaryname) + 1) * (sizeof(char)));
            strcpy(foundpath, binaryname);
            return foundpath;
        } else {
	    return NULL;
	}
    }
    
    char *pathvar = getenv("PATH");
    
    char *dir = strtok(pathvar,":");
    while (dir != NULL){
        char searchpth[PROC_PIDPATHINFO_MAXSIZE];
        strcpy(searchpth, dir);
        strcat(searchpth, "/");
        strcat(searchpth, binaryname);
        
        if (file_exist(searchpth)){
            char *foundpath = (char *)malloc((strlen(searchpth) + 1) * (sizeof(char)));
            strcpy(foundpath, searchpth);
            return foundpath;
        }
        
        dir = strtok(NULL, ":");
    }
    return NULL;
}

static bool isShellScript(const char *path){
    FILE *file = fopen(path, "r");
    uint8_t header[2];
    if (fread(header, sizeof(uint8_t), 2, file) == 2){
        if (header[0] == '#' && header[1] == '!'){
            fclose(file);
            return true;
        }
    }
    fclose(file);
    return false;
}

static char *getInterpreter(char *path){
    FILE *file = fopen(path, "r");
    char *interpreterLine = NULL;
    unsigned long lineSize = 0;
    getline(&interpreterLine, &lineSize, file);
    
    char *rawInterpreter = (interpreterLine+2);
    rawInterpreter = strtok(rawInterpreter, " ");
    rawInterpreter = strtok(rawInterpreter, "\n");
    
    char *interpreter = (char *)malloc((strlen(rawInterpreter)+1) * sizeof(char));
    strcpy(interpreter, rawInterpreter);
    
    free(interpreterLine);
    fclose(file);
    return interpreter;
}

static char *fixedCmd(const char *cmdStr){
    char *cmdCpy = (char *)malloc((strlen(cmdStr)+1) * sizeof(char));
    strcpy(cmdCpy, cmdStr);
    
    char *cmd = strtok(cmdCpy, " ");
    
    uint8_t size = strlen(cmd) + 1;
    
    char *args = cmdCpy + size;
    if ((strlen(cmdStr) - strlen(cmd)) == 0)
        args = NULL;
    
    char *abs_path = searchpath(cmd);
    if (abs_path){
        bool isScript = isShellScript(abs_path);
        if (isScript){
            char *interpreter = getInterpreter(abs_path);
            
            uint8_t commandSize = strlen(interpreter) + 1 + strlen(abs_path);
            
            if (args){
                commandSize += 1 + strlen(args);
            }
            
            char *rawCommand = (char *)malloc(sizeof(char) * (commandSize + 1));
            strcpy(rawCommand, interpreter);
            strcat(rawCommand, " ");
            strcat(rawCommand, abs_path);
            
            if (args){
                strcat(rawCommand, " ");
                strcat(rawCommand, args);
            }
	    rawCommand[(commandSize)+1] = '\0';
            
            free(interpreter);
            free(abs_path);
            free(cmdCpy);
            
            return rawCommand;
        } else {
            uint8_t commandSize = strlen(abs_path);
            
            if (args){
                commandSize += 1 + strlen(args);
            }
            
            char *rawCommand = (char *)malloc(sizeof(char) * (commandSize + 1));
            strcat(rawCommand, abs_path);
            
            if (args){
                strcat(rawCommand, " ");
                strcat(rawCommand, args);
            }
	    rawCommand[(commandSize)+1] = '\0';
            
            free(abs_path);
            free(cmdCpy);
            
            return rawCommand;
        }
    }
    return cmdCpy;
}

int RunCmd(const char *cmd) {
    pid_t pid;
    char *rawCmd = fixedCmd(cmd);
    char *argv[] = {"sh", "-c", (char*)rawCmd, NULL};
    int status;
    status = posix_spawn(&pid, "/bin/sh", NULL, NULL, argv, environ);
    if (status == 0) {
        if (waitpid(pid, &status, 0) == -1) {
            perror("waitpid");
        }
    } else {
        printf("posix_spawn: %s\n", strerror(status));
    }
    free(rawCmd);
    return status;
}

									/*}}}*/

// CopyFile - Buffered copy of a file					/*{{{*/
// ---------------------------------------------------------------------
/* The caller is expected to set things so that failure causes erasure */
bool CopyFile(FileFd &From,FileFd &To)
{
   if (From.IsOpen() == false || To.IsOpen() == false ||
	 From.Failed() == true || To.Failed() == true)
      return false;

   // Buffered copy between fds
   constexpr size_t BufSize = APT_BUFFER_SIZE;
   std::unique_ptr<unsigned char[]> Buf(new unsigned char[BufSize]);
   unsigned long long ToRead = 0;
   do {
      if (From.Read(Buf.get(),BufSize, &ToRead) == false ||
	  To.Write(Buf.get(),ToRead) == false)
	 return false;
   } while (ToRead != 0);

   return true;
}
									/*}}}*/
bool RemoveFile(char const * const Function, std::string const &FileName)/*{{{*/
{
   if (FileName == "/dev/null")
      return true;
   errno = 0;
   if (unlink(FileName.c_str()) != 0)
   {
      if (errno == ENOENT)
	 return true;

      return _error->WarningE(Function,_("Problem unlinking the file %s"), FileName.c_str());
   }
   return true;
}
									/*}}}*/
// GetLock - Gets a lock file						/*{{{*/
// ---------------------------------------------------------------------
/* This will create an empty file of the given name and lock it. Once this
   is done all other calls to GetLock in any other process will fail with
   -1. The return result is the fd of the file, the call should call
   close at some time. */
int GetLock(string File,bool Errors)
{
   // GetLock() is used in aptitude on directories with public-write access
   // Use O_NOFOLLOW here to prevent symlink traversal attacks
   int FD = open(File.c_str(),O_RDWR | O_CREAT | O_NOFOLLOW,0640);
   if (FD < 0)
   {
      // Read only .. can't have locking problems there.
      if (errno == EROFS)
      {
	 _error->Warning(_("Not using locking for read only lock file %s"),File.c_str());
	 return dup(0);       // Need something for the caller to close
      }
      
      if (Errors == true)
	 _error->Errno("open",_("Could not open lock file %s"),File.c_str());

      // Feh.. We do this to distinguish the lock vs open case..
      errno = EPERM;
      return -1;
   }
   SetCloseExec(FD,true);
      
   // Acquire a write lock
   struct flock fl;
   fl.l_type = F_WRLCK;
   fl.l_whence = SEEK_SET;
   fl.l_start = 0;
   fl.l_len = 0;
   if (fcntl(FD,F_SETLK,&fl) == -1)
   {
      // always close to not leak resources
      int Tmp = errno;
      close(FD);
      errno = Tmp;

      if (errno == ENOLCK)
      {
	 _error->Warning(_("Not using locking for nfs mounted lock file %s"),File.c_str());
	 return dup(0);       // Need something for the caller to close	 
      }
  
      if (Errors == true)
	 _error->Errno("open",_("Could not get lock %s"),File.c_str());
      
      return -1;
   }

   return FD;
}
									/*}}}*/
// FileExists - Check if a file exists					/*{{{*/
// ---------------------------------------------------------------------
/* Beware: Directories are also files! */
bool FileExists(string File)
{
   struct stat Buf;
   if (stat(File.c_str(),&Buf) != 0)
      return false;
   return true;
}
									/*}}}*/
// RealFileExists - Check if a file exists and if it is really a file	/*{{{*/
// ---------------------------------------------------------------------
/* */
bool RealFileExists(string File)
{
   struct stat Buf;
   if (stat(File.c_str(),&Buf) != 0)
      return false;
   return ((Buf.st_mode & S_IFREG) != 0);
}
									/*}}}*/
// DirectoryExists - Check if a directory exists and is really one	/*{{{*/
// ---------------------------------------------------------------------
/* */
bool DirectoryExists(string const &Path)
{
   struct stat Buf;
   if (stat(Path.c_str(),&Buf) != 0)
      return false;
   return ((Buf.st_mode & S_IFDIR) != 0);
}
									/*}}}*/
// CreateDirectory - poor man's mkdir -p guarded by a parent directory	/*{{{*/
// ---------------------------------------------------------------------
/* This method will create all directories needed for path in good old
   mkdir -p style but refuses to do this if Parent is not a prefix of
   this Path. Example: /var/cache/ and /var/cache/apt/archives are given,
   so it will create apt/archives if /var/cache exists - on the other
   hand if the parent is /var/lib the creation will fail as this path
   is not a parent of the path to be generated. */
bool CreateDirectory(string const &Parent, string const &Path)
{
   if (Parent.empty() == true || Path.empty() == true)
      return false;

   if (DirectoryExists(Path) == true)
      return true;

   if (DirectoryExists(Parent) == false)
      return false;

   // we are not going to create directories "into the blue"
   if (Path.compare(0, Parent.length(), Parent) != 0)
      return false;

   vector<string> const dirs = VectorizeString(Path.substr(Parent.size()), '/');
   string progress = Parent;
   for (vector<string>::const_iterator d = dirs.begin(); d != dirs.end(); ++d)
   {
      if (d->empty() == true)
	 continue;

      progress.append("/").append(*d);
      if (DirectoryExists(progress) == true)
	 continue;

      if (mkdir(progress.c_str(), 0755) != 0)
	 return false;
   }
   return true;
}
									/*}}}*/
// CreateAPTDirectoryIfNeeded - ensure that the given directory exists		/*{{{*/
// ---------------------------------------------------------------------
/* a small wrapper around CreateDirectory to check if it exists and to
   remove the trailing "/apt/" from the parent directory if needed */
bool CreateAPTDirectoryIfNeeded(string const &Parent, string const &Path)
{
   if (DirectoryExists(Path) == true)
      return true;

   size_t const len = Parent.size();
   if (len > 5 && Parent.find("/apt/", len - 6, 5) == len - 5)
   {
      if (CreateDirectory(Parent.substr(0,len-5), Path) == true)
	 return true;
   }
   else if (CreateDirectory(Parent, Path) == true)
      return true;

   return false;
}
									/*}}}*/
// GetListOfFilesInDir - returns a vector of files in the given dir	/*{{{*/
// ---------------------------------------------------------------------
/* If an extension is given only files with this extension are included
   in the returned vector, otherwise every "normal" file is included. */
std::vector<string> GetListOfFilesInDir(string const &Dir, string const &Ext,
					bool const &SortList, bool const &AllowNoExt)
{
   std::vector<string> ext;
   ext.reserve(2);
   if (Ext.empty() == false)
      ext.push_back(Ext);
   if (AllowNoExt == true && ext.empty() == false)
      ext.push_back("");
   return GetListOfFilesInDir(Dir, ext, SortList);
}
std::vector<string> GetListOfFilesInDir(string const &Dir, std::vector<string> const &Ext,
					bool const &SortList)
{
   // Attention debuggers: need to be set with the environment config file!
   bool const Debug = _config->FindB("Debug::GetListOfFilesInDir", false);
   if (Debug == true)
   {
      std::clog << "Accept in " << Dir << " only files with the following " << Ext.size() << " extensions:" << std::endl;
      if (Ext.empty() == true)
	 std::clog << "\tNO extension" << std::endl;
      else
	 for (std::vector<string>::const_iterator e = Ext.begin();
	      e != Ext.end(); ++e)
	    std::clog << '\t' << (e->empty() == true ? "NO" : *e) << " extension" << std::endl;
   }

   std::vector<string> List;

   if (DirectoryExists(Dir) == false)
   {
      _error->Error(_("List of files can't be created as '%s' is not a directory"), Dir.c_str());
      return List;
   }

   Configuration::MatchAgainstConfig SilentIgnore("Dir::Ignore-Files-Silently");
   DIR *D = opendir(Dir.c_str());
   if (D == 0) 
   {
      _error->Errno("opendir",_("Unable to read %s"),Dir.c_str());
      return List;
   }

   for (struct dirent *Ent = readdir(D); Ent != 0; Ent = readdir(D)) 
   {
      // skip "hidden" files
      if (Ent->d_name[0] == '.')
	 continue;

      // Make sure it is a file and not something else
      string const File = flCombine(Dir,Ent->d_name);
#ifdef _DIRENT_HAVE_D_TYPE
      if (Ent->d_type != DT_REG)
#endif
      {
	 if (RealFileExists(File) == false)
	 {
	    // do not show ignoration warnings for directories
	    if (
#ifdef _DIRENT_HAVE_D_TYPE
		Ent->d_type == DT_DIR ||
#endif
		DirectoryExists(File) == true)
	       continue;
	    if (SilentIgnore.Match(Ent->d_name) == false)
	       _error->Notice(_("Ignoring '%s' in directory '%s' as it is not a regular file"), Ent->d_name, Dir.c_str());
	    continue;
	 }
      }

      // check for accepted extension:
      // no extension given -> periods are bad as hell!
      // extensions given -> "" extension allows no extension
      if (Ext.empty() == false)
      {
	 string d_ext = flExtension(Ent->d_name);
	 if (d_ext == Ent->d_name) // no extension
	 {
	    if (std::find(Ext.begin(), Ext.end(), "") == Ext.end())
	    {
	       if (Debug == true)
		  std::clog << "Bad file: " << Ent->d_name << " → no extension" << std::endl;
	       if (SilentIgnore.Match(Ent->d_name) == false)
		  _error->Notice(_("Ignoring file '%s' in directory '%s' as it has no filename extension"), Ent->d_name, Dir.c_str());
	       continue;
	    }
	 }
	 else if (std::find(Ext.begin(), Ext.end(), d_ext) == Ext.end())
	 {
	    if (Debug == true)
	       std::clog << "Bad file: " << Ent->d_name << " → bad extension »" << flExtension(Ent->d_name) << "«" << std::endl;
	    if (SilentIgnore.Match(Ent->d_name) == false)
	       _error->Notice(_("Ignoring file '%s' in directory '%s' as it has an invalid filename extension"), Ent->d_name, Dir.c_str());
	    continue;
	 }
      }

      // Skip bad filenames ala run-parts
      const char *C = Ent->d_name;
      for (; *C != 0; ++C)
	 if (isalpha(*C) == 0 && isdigit(*C) == 0
	     && *C != '_' && *C != '-' && *C != ':') {
	    // no required extension -> dot is a bad character
	    if (*C == '.' && Ext.empty() == false)
	       continue;
	    break;
	 }

      // we don't reach the end of the name -> bad character included
      if (*C != 0)
      {
	 if (Debug == true)
	    std::clog << "Bad file: " << Ent->d_name << " → bad character »"
	       << *C << "« in filename (period allowed: " << (Ext.empty() ? "no" : "yes") << ")" << std::endl;
	 continue;
      }

      // skip filenames which end with a period. These are never valid
      if (*(C - 1) == '.')
      {
	 if (Debug == true)
	    std::clog << "Bad file: " << Ent->d_name << " → Period as last character" << std::endl;
	 continue;
      }

      if (Debug == true)
	 std::clog << "Accept file: " << Ent->d_name << " in " << Dir << std::endl;
      List.push_back(File);
   }
   closedir(D);

   if (SortList == true)
      std::sort(List.begin(),List.end());
   return List;
}
std::vector<string> GetListOfFilesInDir(string const &Dir, bool SortList)
{
   bool const Debug = _config->FindB("Debug::GetListOfFilesInDir", false);
   if (Debug == true)
      std::clog << "Accept in " << Dir << " all regular files" << std::endl;

   std::vector<string> List;

   if (DirectoryExists(Dir) == false)
   {
      _error->Error(_("List of files can't be created as '%s' is not a directory"), Dir.c_str());
      return List;
   }

   DIR *D = opendir(Dir.c_str());
   if (D == 0)
   {
      _error->Errno("opendir",_("Unable to read %s"),Dir.c_str());
      return List;
   }

   for (struct dirent *Ent = readdir(D); Ent != 0; Ent = readdir(D)) 
   {
      // skip "hidden" files
      if (Ent->d_name[0] == '.')
	 continue;

      // Make sure it is a file and not something else
      string const File = flCombine(Dir,Ent->d_name);
#ifdef _DIRENT_HAVE_D_TYPE
      if (Ent->d_type != DT_REG)
#endif
      {
	 if (RealFileExists(File) == false)
	 {
	    if (Debug == true)
	       std::clog << "Bad file: " << Ent->d_name << " → it is not a real file" << std::endl;
	    continue;
	 }
      }

      // Skip bad filenames ala run-parts
      const char *C = Ent->d_name;
      for (; *C != 0; ++C)
	 if (isalpha(*C) == 0 && isdigit(*C) == 0
	     && *C != '_' && *C != '-' && *C != '.')
	    break;

      // we don't reach the end of the name -> bad character included
      if (*C != 0)
      {
	 if (Debug == true)
	    std::clog << "Bad file: " << Ent->d_name << " → bad character »" << *C << "« in filename" << std::endl;
	 continue;
      }

      // skip filenames which end with a period. These are never valid
      if (*(C - 1) == '.')
      {
	 if (Debug == true)
	    std::clog << "Bad file: " << Ent->d_name << " → Period as last character" << std::endl;
	 continue;
      }

      if (Debug == true)
	 std::clog << "Accept file: " << Ent->d_name << " in " << Dir << std::endl;
      List.push_back(File);
   }
   closedir(D);

   if (SortList == true)
      std::sort(List.begin(),List.end());
   return List;
}
									/*}}}*/
// SafeGetCWD - This is a safer getcwd that returns a dynamic string	/*{{{*/
// ---------------------------------------------------------------------
/* We return / on failure. */
string SafeGetCWD()
{
   // Stash the current dir.
   char S[300];
   S[0] = 0;
   if (getcwd(S,sizeof(S)-2) == 0)
      return "/";
   unsigned int Len = strlen(S);
   S[Len] = '/';
   S[Len+1] = 0;
   return S;
}
									/*}}}*/
// GetModificationTime - Get the mtime of the given file or -1 on error /*{{{*/
// ---------------------------------------------------------------------
/* We return / on failure. */
time_t GetModificationTime(string const &Path)
{
   struct stat St;
   if (stat(Path.c_str(), &St) < 0)
      return -1;
   return  St.st_mtime;
}
									/*}}}*/
// flNotDir - Strip the directory from the filename			/*{{{*/
// ---------------------------------------------------------------------
/* */
string flNotDir(string File)
{
   string::size_type Res = File.rfind('/');
   if (Res == string::npos)
      return File;
   Res++;
   return string(File,Res,Res - File.length());
}
									/*}}}*/
// flNotFile - Strip the file from the directory name			/*{{{*/
// ---------------------------------------------------------------------
/* Result ends in a / */
string flNotFile(string File)
{
   string::size_type Res = File.rfind('/');
   if (Res == string::npos)
      return "./";
   Res++;
   return string(File,0,Res);
}
									/*}}}*/
// flExtension - Return the extension for the file			/*{{{*/
// ---------------------------------------------------------------------
/* */
string flExtension(string File)
{
   string::size_type Res = File.rfind('.');
   if (Res == string::npos)
      return File;
   Res++;
   return string(File,Res,Res - File.length());
}
									/*}}}*/
// flNoLink - If file is a symlink then deref it			/*{{{*/
// ---------------------------------------------------------------------
/* If the name is not a link then the returned path is the input. */
string flNoLink(string File)
{
   struct stat St;
   if (lstat(File.c_str(),&St) != 0 || S_ISLNK(St.st_mode) == 0)
      return File;
   if (stat(File.c_str(),&St) != 0)
      return File;
   
   /* Loop resolving the link. There is no need to limit the number of 
      loops because the stat call above ensures that the symlink is not 
      circular */
   char Buffer[1024];
   string NFile = File;
   while (1)
   {
      // Read the link
      ssize_t Res;
      if ((Res = readlink(NFile.c_str(),Buffer,sizeof(Buffer))) <= 0 || 
	  (size_t)Res >= sizeof(Buffer))
	  return File;
      
      // Append or replace the previous path
      Buffer[Res] = 0;
      if (Buffer[0] == '/')
	 NFile = Buffer;
      else
	 NFile = flNotFile(NFile) + Buffer;
      
      // See if we are done
      if (lstat(NFile.c_str(),&St) != 0)
	 return File;
      if (S_ISLNK(St.st_mode) == 0)
	 return NFile;      
   }   
}
									/*}}}*/
// flCombine - Combine a file and a directory				/*{{{*/
// ---------------------------------------------------------------------
/* If the file is an absolute path then it is just returned, otherwise
   the directory is pre-pended to it. */
string flCombine(string Dir,string File)
{
   if (File.empty() == true)
      return string();
   
   if (File[0] == '/' || Dir.empty() == true)
      return File;
   if (File.length() >= 2 && File[0] == '.' && File[1] == '/')
      return File;
   if (Dir[Dir.length()-1] == '/')
      return Dir + File;
   return Dir + '/' + File;
}
									/*}}}*/
// flAbsPath - Return the absolute path of the filename			/*{{{*/
// ---------------------------------------------------------------------
/* */
string flAbsPath(string File)
{
   char *p = realpath(File.c_str(), NULL);
   if (p == NULL)
   {
      _error->Errno("realpath", "flAbsPath on %s failed", File.c_str());
      return "";
   }
   std::string AbsPath(p);
   free(p);
   return AbsPath;
}
									/*}}}*/
std::string flNormalize(std::string file)				/*{{{*/
{
   if (file.empty())
      return file;
   // do some normalisation by removing // and /./ from the path
   size_t found = string::npos;
   while ((found = file.find("/./")) != string::npos)
      file.replace(found, 3, "/");
   while ((found = file.find("//")) != string::npos)
      file.replace(found, 2, "/");

   if (APT::String::Startswith(file, "/dev/null"))
   {
      file.erase(strlen("/dev/null"));
      return file;
   }
   return file;
}
									/*}}}*/
// SetCloseExec - Set the close on exec flag				/*{{{*/
// ---------------------------------------------------------------------
/* */
void SetCloseExec(int Fd,bool Close)
{   
   if (fcntl(Fd,F_SETFD,(Close == false)?0:FD_CLOEXEC) != 0)
   {
      cerr << "FATAL -> Could not set close on exec " << strerror(errno) << endl;
      exit(100);
   }
}
									/*}}}*/
// SetNonBlock - Set the nonblocking flag				/*{{{*/
// ---------------------------------------------------------------------
/* */
void SetNonBlock(int Fd,bool Block)
{   
   int Flags = fcntl(Fd,F_GETFL) & (~O_NONBLOCK);
   if (fcntl(Fd,F_SETFL,Flags | ((Block == false)?0:O_NONBLOCK)) != 0)
   {
      cerr << "FATAL -> Could not set non-blocking flag " << strerror(errno) << endl;
      exit(100);
   }
}
									/*}}}*/
// WaitFd - Wait for a FD to become readable				/*{{{*/
// ---------------------------------------------------------------------
/* This waits for a FD to become readable using select. It is useful for
   applications making use of non-blocking sockets. The timeout is 
   in seconds. */
bool WaitFd(int Fd,bool write,unsigned long timeout)
{
   fd_set Set;
   struct timeval tv;
   FD_ZERO(&Set);
   FD_SET(Fd,&Set);
   tv.tv_sec = timeout;
   tv.tv_usec = 0;
   if (write == true) 
   {      
      int Res;
      do
      {
	 Res = select(Fd+1,0,&Set,0,(timeout != 0?&tv:0));
      }
      while (Res < 0 && errno == EINTR);
      
      if (Res <= 0)
	 return false;
   } 
   else 
   {
      int Res;
      do
      {
	 Res = select(Fd+1,&Set,0,0,(timeout != 0?&tv:0));
      }
      while (Res < 0 && errno == EINTR);
      
      if (Res <= 0)
	 return false;
   }
   
   return true;
}
									/*}}}*/
// MergeKeepFdsFromConfiguration - Merge APT::Keep-Fds configuration	/*{{{*/
// ---------------------------------------------------------------------
/* This is used to merge the APT::Keep-Fds with the provided KeepFDs
 * set.
 */
void MergeKeepFdsFromConfiguration(std::set<int> &KeepFDs)
{
      Configuration::Item const *Opts = _config->Tree("APT::Keep-Fds");
      if (Opts != 0 && Opts->Child != 0)
      {
	 Opts = Opts->Child;
	 for (; Opts != 0; Opts = Opts->Next)
	 {
	    if (Opts->Value.empty() == true)
	       continue;
	    int fd = atoi(Opts->Value.c_str());
	    KeepFDs.insert(fd);
	 }
      }
}
									/*}}}*/
// ExecFork - Magical fork that sanitizes the context before execing	/*{{{*/
// ---------------------------------------------------------------------
/* This is used if you want to cleanse the environment for the forked 
   child, it fixes up the important signals and nukes all of the fds,
   otherwise acts like normal fork. */
pid_t ExecFork()
{
      set<int> KeepFDs;
      // we need to merge the Keep-Fds as external tools like 
      // debconf-apt-progress use it
      MergeKeepFdsFromConfiguration(KeepFDs);
      return ExecFork(KeepFDs);
}

pid_t ExecFork(std::set<int> KeepFDs)
{
   // Fork off the process
   pid_t Process = fork();
   if (Process < 0)
   {
      cerr << "FATAL -> Failed to fork." << endl;
      exit(100);
   }

   // Spawn the subprocess
   if (Process == 0)
   {
      // Setup the signals
      signal(SIGPIPE,SIG_DFL);
      signal(SIGQUIT,SIG_DFL);
      signal(SIGINT,SIG_DFL);
      signal(SIGWINCH,SIG_DFL);
      signal(SIGCONT,SIG_DFL);
      signal(SIGTSTP,SIG_DFL);

      DIR *dir = opendir("/proc/self/fd");
      if (dir != NULL)
      {
	 struct dirent *ent;
	 while ((ent = readdir(dir)))
	 {
	    int fd = atoi(ent->d_name);
	    // If fd > 0, it was a fd number and not . or ..
	    if (fd >= 3 && KeepFDs.find(fd) == KeepFDs.end())
	       fcntl(fd,F_SETFD,FD_CLOEXEC);
	 }
	 closedir(dir);
      } else {
	 long ScOpenMax = sysconf(_SC_OPEN_MAX);
	 // Close all of our FDs - just in case
	 for (int K = 3; K != ScOpenMax; K++)
	 {
	    if(KeepFDs.find(K) == KeepFDs.end())
	       fcntl(K,F_SETFD,FD_CLOEXEC);
	 }
      }
   }
   
   return Process;
}
									/*}}}*/
// ExecWait - Fancy waitpid						/*{{{*/
// ---------------------------------------------------------------------
/* Waits for the given sub process. If Reap is set then no errors are 
   generated. Otherwise a failed subprocess will generate a proper descriptive
   message */
bool ExecWait(pid_t Pid,const char *Name,bool Reap)
{
   if (Pid <= 1)
      return true;
   
   // Wait and collect the error code
   int Status;
   while (waitpid(Pid,&Status,0) != Pid)
   {
      if (errno == EINTR)
	 continue;

      if (Reap == true)
	 return false;
      
      return _error->Error(_("Waited for %s but it wasn't there"),Name);
   }

   
   // Check for an error code.
   if (WIFEXITED(Status) == 0 || WEXITSTATUS(Status) != 0)
   {
      if (Reap == true)
	 return false;
      if (WIFSIGNALED(Status) != 0)
      {
	 if( WTERMSIG(Status) == SIGSEGV)
	    return _error->Error(_("Sub-process %s received a segmentation fault."),Name);
	 else 
	    return _error->Error(_("Sub-process %s received signal %u."),Name, WTERMSIG(Status));
      }

      if (WIFEXITED(Status) != 0)
	 return _error->Error(_("Sub-process %s returned an error code (%u)"),Name,WEXITSTATUS(Status));
      
      return _error->Error(_("Sub-process %s exited unexpectedly"),Name);
   }      
   
   return true;
}
									/*}}}*/
// StartsWithGPGClearTextSignature - Check if a file is Pgp/GPG clearsigned	/*{{{*/
bool StartsWithGPGClearTextSignature(string const &FileName)
{
   static const char* SIGMSG = "-----BEGIN PGP SIGNED MESSAGE-----\n";
   char buffer[strlen(SIGMSG)+1];
   FILE* gpg = fopen(FileName.c_str(), "r");
   if (gpg == NULL)
      return false;

   char const * const test = fgets(buffer, sizeof(buffer), gpg);
   fclose(gpg);
   if (test == NULL || strcmp(buffer, SIGMSG) != 0)
      return false;

   return true;
}
									/*}}}*/
// ChangeOwnerAndPermissionOfFile - set file attributes to requested values /*{{{*/
bool ChangeOwnerAndPermissionOfFile(char const * const requester, char const * const file, char const * const user, char const * const group, mode_t const mode)
{
   if (strcmp(file, "/dev/null") == 0)
      return true;
   bool Res = true;
   if (getuid() == 0 && strlen(user) != 0 && strlen(group) != 0) // if we aren't root, we can't chown, so don't try it
   {
      // ensure the file is owned by root and has good permissions
      struct passwd const * const pw = getpwnam(user);
      struct group const * const gr = getgrnam(group);
      if (pw != NULL && gr != NULL && lchown(file, pw->pw_uid, gr->gr_gid) != 0)
	 Res &= _error->WarningE(requester, "chown to %s:%s of file %s failed", user, group, file);
   }
   struct stat Buf;
   if (lstat(file, &Buf) != 0 || S_ISLNK(Buf.st_mode))
      return Res;
   if (chmod(file, mode) != 0)
      Res &= _error->WarningE(requester, "chmod 0%o of file %s failed", mode, file);
   return Res;
}
									/*}}}*/

struct APT_HIDDEN simple_buffer {							/*{{{*/
   size_t buffersize_max = 0;
   unsigned long long bufferstart = 0;
   unsigned long long bufferend = 0;
   char *buffer = nullptr;

   simple_buffer() {
      reset(4096);
   }
   ~simple_buffer() {
      delete[] buffer;
   }

   const char *get() const { return buffer + bufferstart; }
   char *get() { return buffer + bufferstart; }
   const char *getend() const { return buffer + bufferend; }
   char *getend() { return buffer + bufferend; }
   bool empty() const { return bufferend <= bufferstart; }
   bool full() const { return bufferend == buffersize_max; }
   unsigned long long free() const { return buffersize_max - bufferend; }
   unsigned long long size() const { return bufferend-bufferstart; }
   void reset(size_t size)
   {
      if (size > buffersize_max) {
	 delete[] buffer;
	 buffersize_max = size;
	 buffer = new char[size];
      }
      reset();
   }
   void reset() { bufferend = bufferstart = 0; }
   ssize_t read(void *to, unsigned long long requested_size) APT_MUSTCHECK
   {
      if (size() < requested_size)
	 requested_size = size();
      memcpy(to, buffer + bufferstart, requested_size);
      bufferstart += requested_size;
      if (bufferstart == bufferend)
	 bufferstart = bufferend = 0;
      return requested_size;
   }
   ssize_t write(const void *from, unsigned long long requested_size) APT_MUSTCHECK
   {
      if (free() < requested_size)
	 requested_size = free();
      memcpy(getend(), from, requested_size);
      bufferend += requested_size;
      if (bufferstart == bufferend)
	 bufferstart = bufferend = 0;
      return requested_size;
   }
};
									/*}}}*/

class APT_HIDDEN FileFdPrivate {							/*{{{*/
   friend class BufferedWriteFileFdPrivate;
protected:
   FileFd * const filefd;
   simple_buffer buffer;
   int compressed_fd;
   pid_t compressor_pid;
   bool is_pipe;
   APT::Configuration::Compressor compressor;
   unsigned int openmode;
   unsigned long long seekpos;
public:

   explicit FileFdPrivate(FileFd * const pfilefd) : filefd(pfilefd),
      compressed_fd(-1), compressor_pid(-1), is_pipe(false),
      openmode(0), seekpos(0) {};
   virtual APT::Configuration::Compressor get_compressor() const
   {
      return compressor;
   }
   virtual void set_compressor(APT::Configuration::Compressor const &compressor)
   {
      this->compressor = compressor;
   }
   virtual unsigned int get_openmode() const
   {
      return openmode;
   }
   virtual void set_openmode(unsigned int openmode)
   {
      this->openmode = openmode;
   }
   virtual bool get_is_pipe() const
   {
      return is_pipe;
   }
   virtual void set_is_pipe(bool is_pipe)
   {
      this->is_pipe = is_pipe;
   }
   virtual unsigned long long get_seekpos() const
   {
      return seekpos;
   }
   virtual void set_seekpos(unsigned long long seekpos)
   {
      this->seekpos = seekpos;
   }

   virtual bool InternalOpen(int const iFd, unsigned int const Mode) = 0;
   ssize_t InternalRead(void * To, unsigned long long Size)
   {
      // Drain the buffer if needed.
      if (buffer.empty() == false)
      {
	 return buffer.read(To, Size);
      }
      return InternalUnbufferedRead(To, Size);
   }
   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) = 0;
   virtual bool InternalReadError() { return filefd->FileFdErrno("read",_("Read error")); }
   virtual char * InternalReadLine(char * To, unsigned long long Size)
   {
      if (unlikely(Size == 0))
	 return nullptr;
      // Read one byte less than buffer size to have space for trailing 0.
      --Size;

      char * const InitialTo = To;

      while (Size > 0) {
	 if (buffer.empty() == true)
	 {
	    buffer.reset();
	    unsigned long long actualread = 0;
	    if (filefd->Read(buffer.getend(), buffer.free(), &actualread) == false)
	       return nullptr;
	    buffer.bufferend = actualread;
	    if (buffer.size() == 0)
	    {
	       if (To == InitialTo)
		  return nullptr;
	       break;
	    }
	    filefd->Flags &= ~FileFd::HitEof;
	 }

	 unsigned long long const OutputSize = std::min(Size, buffer.size());
	 char const * const newline = static_cast<char const * const>(memchr(buffer.get(), '\n', OutputSize));
	 // Read until end of line or up to Size bytes from the buffer.
	 unsigned long long actualread = buffer.read(To,
						     (newline != nullptr)
						     ? (newline - buffer.get()) + 1
						     : OutputSize);
	 To += actualread;
	 Size -= actualread;
	 if (newline != nullptr)
	    break;
      }
      *To = '\0';
      return InitialTo;
   }
   virtual bool InternalFlush()
   {
      return true;
   }
   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) = 0;
   virtual bool InternalWriteError() { return filefd->FileFdErrno("write",_("Write error")); }
   virtual bool InternalSeek(unsigned long long const To)
   {
      // Our poor man seeking is costly, so try to avoid it
      unsigned long long const iseekpos = filefd->Tell();
      if (iseekpos == To)
	 return true;
      else if (iseekpos < To)
	 return filefd->Skip(To - iseekpos);

      if ((openmode & FileFd::ReadOnly) != FileFd::ReadOnly)
	 return filefd->FileFdError("Reopen is only implemented for read-only files!");
      InternalClose(filefd->FileName);
      if (filefd->iFd != -1)
	 close(filefd->iFd);
      filefd->iFd = -1;
      if (filefd->TemporaryFileName.empty() == false)
	 filefd->iFd = open(filefd->TemporaryFileName.c_str(), O_RDONLY);
      else if (filefd->FileName.empty() == false)
	 filefd->iFd = open(filefd->FileName.c_str(), O_RDONLY);
      else
      {
	 if (compressed_fd > 0)
	    if (lseek(compressed_fd, 0, SEEK_SET) != 0)
	       filefd->iFd = compressed_fd;
	 if (filefd->iFd < 0)
	    return filefd->FileFdError("Reopen is not implemented for pipes opened with FileFd::OpenDescriptor()!");
      }

      if (filefd->OpenInternDescriptor(openmode, compressor) == false)
	 return filefd->FileFdError("Seek on file %s because it couldn't be reopened", filefd->FileName.c_str());

      buffer.reset();
      set_seekpos(0);
      if (To != 0)
	 return filefd->Skip(To);

      seekpos = To;
      return true;
   }
   virtual bool InternalSkip(unsigned long long Over)
   {
      unsigned long long constexpr buffersize = 1024;
      char buffer[buffersize];
      while (Over != 0)
      {
	 unsigned long long toread = std::min(buffersize, Over);
	 if (filefd->Read(buffer, toread) == false)
	    return filefd->FileFdError("Unable to seek ahead %llu",Over);
	 Over -= toread;
      }
      return true;
   }
   virtual bool InternalTruncate(unsigned long long const)
   {
      return filefd->FileFdError("Truncating compressed files is not implemented (%s)", filefd->FileName.c_str());
   }
   virtual unsigned long long InternalTell()
   {
      // In theory, we could just return seekpos here always instead of
      // seeking around, but not all users of FileFd use always Seek() and co
      // so d->seekpos isn't always true and we can just use it as a hint if
      // we have nothing else, but not always as an authority…
      return seekpos - buffer.size();
   }
   virtual unsigned long long InternalSize()
   {
      unsigned long long size = 0;
      unsigned long long const oldSeek = filefd->Tell();
      unsigned long long constexpr ignoresize = 1024;
      char ignore[ignoresize];
      unsigned long long read = 0;
      do {
	 if (filefd->Read(ignore, ignoresize, &read) == false)
	 {
	    filefd->Seek(oldSeek);
	    return 0;
	 }
      } while(read != 0);
      size = filefd->Tell();
      filefd->Seek(oldSeek);
      return size;
   }
   virtual bool InternalClose(std::string const &FileName) = 0;
   virtual bool InternalStream() const { return false; }
   virtual bool InternalAlwaysAutoClose() const { return true; }

   virtual ~FileFdPrivate() {}
};
									/*}}}*/
class APT_HIDDEN BufferedWriteFileFdPrivate : public FileFdPrivate {	/*{{{*/
protected:
   FileFdPrivate *wrapped;
   simple_buffer writebuffer;

public:

   explicit BufferedWriteFileFdPrivate(FileFdPrivate *Priv) :
      FileFdPrivate(Priv->filefd), wrapped(Priv) {};

   virtual APT::Configuration::Compressor get_compressor() const APT_OVERRIDE
   {
      return wrapped->get_compressor();
   }
   virtual void set_compressor(APT::Configuration::Compressor const &compressor)  APT_OVERRIDE
   {
      return wrapped->set_compressor(compressor);
   }
   virtual unsigned int get_openmode() const  APT_OVERRIDE
   {
      return wrapped->get_openmode();
   }
   virtual void set_openmode(unsigned int openmode)  APT_OVERRIDE
   {
      return wrapped->set_openmode(openmode);
   }
   virtual bool get_is_pipe() const  APT_OVERRIDE
   {
      return wrapped->get_is_pipe();
   }
   virtual void set_is_pipe(bool is_pipe) APT_OVERRIDE
   {
      FileFdPrivate::set_is_pipe(is_pipe);
      wrapped->set_is_pipe(is_pipe);
   }
   virtual unsigned long long get_seekpos() const APT_OVERRIDE
   {
      return wrapped->get_seekpos();
   }
   virtual void set_seekpos(unsigned long long seekpos) APT_OVERRIDE
   {
      return wrapped->set_seekpos(seekpos);
   }
   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
   {
      if (InternalFlush() == false)
	 return false;
      return wrapped->InternalOpen(iFd, Mode);
   }
   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
   {
      if (InternalFlush() == false)
	 return -1;
      return wrapped->InternalUnbufferedRead(To, Size);

   }
   virtual bool InternalReadError() APT_OVERRIDE
   {
      return wrapped->InternalReadError();
   }
   virtual char * InternalReadLine(char * To, unsigned long long Size) APT_OVERRIDE
   {
      if (InternalFlush() == false)
	 return nullptr;
      return wrapped->InternalReadLine(To, Size);
   }
   virtual bool InternalFlush() APT_OVERRIDE
   {
      while (writebuffer.empty() == false) {
	 auto written = wrapped->InternalWrite(writebuffer.get(),
					       writebuffer.size());
	 // Ignore interrupted syscalls
	 if (written < 0 && errno == EINTR)
	    continue;
	 if (written < 0)
	    return wrapped->InternalWriteError();

	 writebuffer.bufferstart += written;
      }
      writebuffer.reset();
      return wrapped->InternalFlush();
   }
   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
   {
      // Optimisation: If the buffer is empty and we have more to write than
      // would fit in the buffer (or equal number of bytes), write directly.
      if (writebuffer.empty() == true && Size >= writebuffer.free())
	 return wrapped->InternalWrite(From, Size);

      // Write as much into the buffer as possible and then flush if needed
      auto written = writebuffer.write(From, Size);

      if (writebuffer.full() && InternalFlush() == false)
	 return -1;

      return written;
   }
   virtual bool InternalWriteError() APT_OVERRIDE
   {
      return wrapped->InternalWriteError();
   }
   virtual bool InternalSeek(unsigned long long const To) APT_OVERRIDE
   {
      if (InternalFlush() == false)
	 return false;
      return wrapped->InternalSeek(To);
   }
   virtual bool InternalSkip(unsigned long long Over) APT_OVERRIDE
   {
      if (InternalFlush() == false)
	 return false;
      return wrapped->InternalSkip(Over);
   }
   virtual bool InternalTruncate(unsigned long long const Size) APT_OVERRIDE
   {
      if (InternalFlush() == false)
	 return false;
      return wrapped->InternalTruncate(Size);
   }
   virtual unsigned long long InternalTell() APT_OVERRIDE
   {
      if (InternalFlush() == false)
	 return -1;
      return wrapped->InternalTell();
   }
   virtual unsigned long long InternalSize() APT_OVERRIDE
   {
      if (InternalFlush() == false)
	 return -1;
      return wrapped->InternalSize();
   }
   virtual bool InternalClose(std::string const &FileName) APT_OVERRIDE
   {
      return wrapped->InternalClose(FileName);
   }
   virtual bool InternalAlwaysAutoClose() const APT_OVERRIDE
   {
      return wrapped->InternalAlwaysAutoClose();
   }
   virtual ~BufferedWriteFileFdPrivate()
   {
      delete wrapped;
   }
};
									/*}}}*/
class APT_HIDDEN GzipFileFdPrivate: public FileFdPrivate {				/*{{{*/
#ifdef HAVE_ZLIB
public:
   gzFile gz;
   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
   {
      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
	 gz = gzdopen(iFd, "r+");
      else if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
	 gz = gzdopen(iFd, "w");
      else
	 gz = gzdopen(iFd, "r");
      filefd->Flags |= FileFd::Compressed;
      return gz != nullptr;
   }
   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
   {
      return gzread(gz, To, Size);
   }
   virtual bool InternalReadError() APT_OVERRIDE
   {
      int err;
      char const * const errmsg = gzerror(gz, &err);
      if (err != Z_ERRNO)
	 return filefd->FileFdError("gzread: %s (%d: %s)", _("Read error"), err, errmsg);
      return FileFdPrivate::InternalReadError();
   }
   virtual char * InternalReadLine(char * To, unsigned long long Size) APT_OVERRIDE
   {
      return gzgets(gz, To, Size);
   }
   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
   {
      return gzwrite(gz,From,Size);
   }
   virtual bool InternalWriteError() APT_OVERRIDE
   {
      int err;
      char const * const errmsg = gzerror(gz, &err);
      if (err != Z_ERRNO)
	 return filefd->FileFdError("gzwrite: %s (%d: %s)", _("Write error"), err, errmsg);
      return FileFdPrivate::InternalWriteError();
   }
   virtual bool InternalSeek(unsigned long long const To) APT_OVERRIDE
   {
      off_t const res = gzseek(gz, To, SEEK_SET);
      if (res != (off_t)To)
	 return filefd->FileFdError("Unable to seek to %llu", To);
      seekpos = To;
      buffer.reset();
      return true;
   }
   virtual bool InternalSkip(unsigned long long Over) APT_OVERRIDE
   {
      if (Over >= buffer.size())
      {
	 Over -= buffer.size();
	 buffer.reset();
      }
      else
      {
	 buffer.bufferstart += Over;
	 return true;
      }
      if (Over == 0)
	 return true;
      off_t const res = gzseek(gz, Over, SEEK_CUR);
      if (res < 0)
	 return filefd->FileFdError("Unable to seek ahead %llu",Over);
      seekpos = res;
      return true;
   }
   virtual unsigned long long InternalTell() APT_OVERRIDE
   {
      return gztell(gz) - buffer.size();
   }
   virtual unsigned long long InternalSize() APT_OVERRIDE
   {
      unsigned long long filesize = FileFdPrivate::InternalSize();
      // only check gzsize if we are actually a gzip file, just checking for
      // "gz" is not sufficient as uncompressed files could be opened with
      // gzopen in "direct" mode as well
      if (filesize == 0 || gzdirect(gz))
	 return filesize;

      off_t const oldPos = lseek(filefd->iFd, 0, SEEK_CUR);
      /* unfortunately zlib.h doesn't provide a gzsize(), so we have to do
       * this ourselves; the original (uncompressed) file size is the last 32
       * bits of the file */
      // FIXME: Size for gz-files is limited by 32bit… no largefile support
      if (lseek(filefd->iFd, -4, SEEK_END) < 0)
      {
	 filefd->FileFdErrno("lseek","Unable to seek to end of gzipped file");
	 return 0;
      }
      uint32_t size = 0;
      if (read(filefd->iFd, &size, 4) != 4)
      {
	 filefd->FileFdErrno("read","Unable to read original size of gzipped file");
	 return 0;
      }
      size = le32toh(size);

      if (lseek(filefd->iFd, oldPos, SEEK_SET) < 0)
      {
	 filefd->FileFdErrno("lseek","Unable to seek in gzipped file");
	 return 0;
      }
      return size;
   }
   virtual bool InternalClose(std::string const &FileName) APT_OVERRIDE
   {
      if (gz == nullptr)
	 return true;
      int const e = gzclose(gz);
      gz = nullptr;
      // gzdclose() on empty files always fails with "buffer error" here, ignore that
      if (e != 0 && e != Z_BUF_ERROR)
	 return _error->Errno("close",_("Problem closing the gzip file %s"), FileName.c_str());
      return true;
   }

   explicit GzipFileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd), gz(nullptr) {}
   virtual ~GzipFileFdPrivate() { InternalClose(""); }
#endif
};
									/*}}}*/
class APT_HIDDEN Bz2FileFdPrivate: public FileFdPrivate {				/*{{{*/
#ifdef HAVE_BZ2
   BZFILE* bz2;
public:
   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
   {
      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
	 bz2 = BZ2_bzdopen(iFd, "r+");
      else if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
	 bz2 = BZ2_bzdopen(iFd, "w");
      else
	 bz2 = BZ2_bzdopen(iFd, "r");
      filefd->Flags |= FileFd::Compressed;
      return bz2 != nullptr;
   }
   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
   {
      return BZ2_bzread(bz2, To, Size);
   }
   virtual bool InternalReadError() APT_OVERRIDE
   {
      int err;
      char const * const errmsg = BZ2_bzerror(bz2, &err);
      if (err != BZ_IO_ERROR)
	 return filefd->FileFdError("BZ2_bzread: %s %s (%d: %s)", filefd->FileName.c_str(), _("Read error"), err, errmsg);
      return FileFdPrivate::InternalReadError();
   }
   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
   {
      return BZ2_bzwrite(bz2, (void*)From, Size);
   }
   virtual bool InternalWriteError() APT_OVERRIDE
   {
      int err;
      char const * const errmsg = BZ2_bzerror(bz2, &err);
      if (err != BZ_IO_ERROR)
	 return filefd->FileFdError("BZ2_bzwrite: %s %s (%d: %s)", filefd->FileName.c_str(), _("Write error"), err, errmsg);
      return FileFdPrivate::InternalWriteError();
   }
   virtual bool InternalStream() const APT_OVERRIDE { return true; }
   virtual bool InternalClose(std::string const &) APT_OVERRIDE
   {
      if (bz2 == nullptr)
	 return true;
      BZ2_bzclose(bz2);
      bz2 = nullptr;
      return true;
   }

   explicit Bz2FileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd), bz2(nullptr) {}
   virtual ~Bz2FileFdPrivate() { InternalClose(""); }
#endif
};
									/*}}}*/
class APT_HIDDEN Lz4FileFdPrivate: public FileFdPrivate {				/*{{{*/
   static constexpr unsigned long long LZ4_HEADER_SIZE = 19;
   static constexpr unsigned long long LZ4_FOOTER_SIZE = 4;
#ifdef HAVE_LZ4
   LZ4F_decompressionContext_t dctx;
   LZ4F_compressionContext_t cctx;
   LZ4F_errorCode_t res;
   FileFd backend;
   simple_buffer lz4_buffer;
   // Count of bytes that the decompressor expects to read next, or buffer size.
   size_t next_to_load = APT_BUFFER_SIZE;
public:
   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
   {
      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
	 return _error->Error("lz4 only supports write or read mode");

      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly) {
	 res = LZ4F_createCompressionContext(&cctx, LZ4F_VERSION);
	 lz4_buffer.reset(LZ4F_compressBound(APT_BUFFER_SIZE, nullptr)
			  + LZ4_HEADER_SIZE + LZ4_FOOTER_SIZE);
      } else {
	 res = LZ4F_createDecompressionContext(&dctx, LZ4F_VERSION);
	 lz4_buffer.reset(APT_BUFFER_SIZE);
      }

      filefd->Flags |= FileFd::Compressed;

      if (LZ4F_isError(res))
	 return false;

      unsigned int flags = (Mode & (FileFd::WriteOnly|FileFd::ReadOnly));
      if (backend.OpenDescriptor(iFd, flags, FileFd::None, true) == false)
	 return false;

      // Write the file header
      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
      {
	 res = LZ4F_compressBegin(cctx, lz4_buffer.buffer, lz4_buffer.buffersize_max, nullptr);
	 if (LZ4F_isError(res) || backend.Write(lz4_buffer.buffer, res) == false)
	    return false;
      }

      return true;
   }
   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
   {
      /* Keep reading as long as the compressor still wants to read */
      while (next_to_load) {
	 // Fill compressed buffer;
	 if (lz4_buffer.empty()) {
	    unsigned long long read;
	    /* Reset - if LZ4 decompressor wants to read more, allocate more */
	    lz4_buffer.reset(next_to_load);
	    if (backend.Read(lz4_buffer.getend(), lz4_buffer.free(), &read) == false)
	       return -1;
	    lz4_buffer.bufferend += read;

	    /* Expected EOF */
	    if (read == 0) {
	       res = -1;
	       return filefd->FileFdError("LZ4F: %s %s",
					  filefd->FileName.c_str(),
					  _("Unexpected end of file")), -1;
	    }
	 }
	 // Drain compressed buffer as far as possible.
	 size_t in = lz4_buffer.size();
	 size_t out = Size;

	 res = LZ4F_decompress(dctx, To, &out, lz4_buffer.get(), &in, nullptr);
	 if (LZ4F_isError(res))
	       return -1;

	 next_to_load = res;
	 lz4_buffer.bufferstart += in;

	 if (out != 0)
	    return out;
      }

      return 0;
   }
   virtual bool InternalReadError() APT_OVERRIDE
   {
      char const * const errmsg = LZ4F_getErrorName(res);

      return filefd->FileFdError("LZ4F: %s %s (%zu: %s)", filefd->FileName.c_str(), _("Read error"), res, errmsg);
   }
   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
   {
      unsigned long long const towrite = std::min(APT_BUFFER_SIZE, Size);

      res = LZ4F_compressUpdate(cctx,
				lz4_buffer.buffer, lz4_buffer.buffersize_max,
				From, towrite, nullptr);

      if (LZ4F_isError(res) || backend.Write(lz4_buffer.buffer, res) == false)
	 return -1;

      return towrite;
   }
   virtual bool InternalWriteError() APT_OVERRIDE
   {
      char const * const errmsg = LZ4F_getErrorName(res);

      return filefd->FileFdError("LZ4F: %s %s (%zu: %s)", filefd->FileName.c_str(), _("Write error"), res, errmsg);
   }
   virtual bool InternalStream() const APT_OVERRIDE { return true; }

   virtual bool InternalFlush() APT_OVERRIDE
   {
      return backend.Flush();
   }

   virtual bool InternalClose(std::string const &) APT_OVERRIDE
   {
      /* Reset variables */
      res = 0;
      next_to_load = APT_BUFFER_SIZE;

      if (cctx != nullptr)
      {
	 if (filefd->Failed() == false)
	 {
	    res = LZ4F_compressEnd(cctx, lz4_buffer.buffer, lz4_buffer.buffersize_max, nullptr);
	    if (LZ4F_isError(res) || backend.Write(lz4_buffer.buffer, res) == false)
	       return false;
	    if (!backend.Flush())
	       return false;
	 }
	 if (!backend.Close())
	    return false;

	 res = LZ4F_freeCompressionContext(cctx);
	 cctx = nullptr;
      }

      if (dctx != nullptr)
      {
	 res = LZ4F_freeDecompressionContext(dctx);
	 dctx = nullptr;
      }
      if (backend.IsOpen())
      {
	 backend.Close();
	 filefd->iFd = -1;
      }

      return LZ4F_isError(res) == false;
   }

   explicit Lz4FileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd), dctx(nullptr), cctx(nullptr) {}
   virtual ~Lz4FileFdPrivate() {
      InternalClose("");
   }
#endif
};
									/*}}}*/
class APT_HIDDEN LzmaFileFdPrivate: public FileFdPrivate {				/*{{{*/
#ifdef HAVE_LZMA
   struct LZMAFILE {
      FILE* file;
      FileFd * const filefd;
      uint8_t buffer[4096];
      lzma_stream stream;
      lzma_ret err;
      bool eof;
      bool compressing;

      LZMAFILE(FileFd * const fd) : file(nullptr), filefd(fd), eof(false), compressing(false) { buffer[0] = '\0'; }
      ~LZMAFILE()
      {
	 if (compressing == true && filefd->Failed() == false)
	 {
	    size_t constexpr buffersize = sizeof(buffer)/sizeof(buffer[0]);
	    while(true)
	    {
	       stream.avail_out = buffersize;
	       stream.next_out = buffer;
	       err = lzma_code(&stream, LZMA_FINISH);
	       if (err != LZMA_OK && err != LZMA_STREAM_END)
	       {
		  _error->Error("~LZMAFILE: Compress finalisation failed");
		  break;
	       }
	       size_t const n =  buffersize - stream.avail_out;
	       if (n && fwrite(buffer, 1, n, file) != n)
	       {
		  _error->Errno("~LZMAFILE",_("Write error"));
		  break;
	       }
	       if (err == LZMA_STREAM_END)
		  break;
	    }
	 }
	 lzma_end(&stream);
	 fclose(file);
      }
   };
   LZMAFILE* lzma;
   static uint32_t findXZlevel(std::vector<std::string> const &Args)
   {
      for (auto a = Args.rbegin(); a != Args.rend(); ++a)
	 if (a->empty() == false && (*a)[0] == '-' && (*a)[1] != '-')
	 {
	    auto const number = a->find_last_of("0123456789");
	    if (number == std::string::npos)
	       continue;
	    auto const extreme = a->find("e", number);
	    uint32_t level = (extreme != std::string::npos) ? LZMA_PRESET_EXTREME : 0;
	    switch ((*a)[number])
	    {
	       case '0': return level | 0;
	       case '1': return level | 1;
	       case '2': return level | 2;
	       case '3': return level | 3;
	       case '4': return level | 4;
	       case '5': return level | 5;
	       case '6': return level | 6;
	       case '7': return level | 7;
	       case '8': return level | 8;
	       case '9': return level | 9;
	    }
	 }
      return 6;
   }
public:
   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
   {
      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
	 return filefd->FileFdError("ReadWrite mode is not supported for lzma/xz files %s", filefd->FileName.c_str());

      if (lzma == nullptr)
	 lzma = new LzmaFileFdPrivate::LZMAFILE(filefd);
      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
	 lzma->file = fdopen(iFd, "w");
      else
	 lzma->file = fdopen(iFd, "r");
      filefd->Flags |= FileFd::Compressed;
      if (lzma->file == nullptr)
	 return false;

      lzma_stream tmp_stream = LZMA_STREAM_INIT;
      lzma->stream = tmp_stream;

      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
      {
	 uint32_t const xzlevel = findXZlevel(compressor.CompressArgs);
	 if (compressor.Name == "xz")
	 {
	    if (lzma_easy_encoder(&lzma->stream, xzlevel, LZMA_CHECK_CRC64) != LZMA_OK)
	       return false;
	 }
	 else
	 {
	    lzma_options_lzma options;
	    lzma_lzma_preset(&options, xzlevel);
	    if (lzma_alone_encoder(&lzma->stream, &options) != LZMA_OK)
	       return false;
	 }
	 lzma->compressing = true;
      }
      else
      {
	 uint64_t const memlimit = UINT64_MAX;
	 if (compressor.Name == "xz")
	 {
	    if (lzma_auto_decoder(&lzma->stream, memlimit, 0) != LZMA_OK)
	       return false;
	 }
	 else
	 {
	    if (lzma_alone_decoder(&lzma->stream, memlimit) != LZMA_OK)
	       return false;
	 }
	 lzma->compressing = false;
      }
      return true;
   }
   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
   {
      ssize_t Res;
      if (lzma->eof == true)
	 return 0;

      lzma->stream.next_out = (uint8_t *) To;
      lzma->stream.avail_out = Size;
      if (lzma->stream.avail_in == 0)
      {
	 lzma->stream.next_in = lzma->buffer;
	 lzma->stream.avail_in = fread(lzma->buffer, 1, sizeof(lzma->buffer)/sizeof(lzma->buffer[0]), lzma->file);
      }
      lzma->err = lzma_code(&lzma->stream, LZMA_RUN);
      if (lzma->err == LZMA_STREAM_END)
      {
	 lzma->eof = true;
	 Res = Size - lzma->stream.avail_out;
      }
      else if (lzma->err != LZMA_OK)
      {
	 Res = -1;
	 errno = 0;
      }
      else
      {
	 Res = Size - lzma->stream.avail_out;
	 if (Res == 0)
	 {
	    // lzma run was okay, but produced no output…
	    Res = -1;
	    errno = EINTR;
	 }
      }
      return Res;
   }
   virtual bool InternalReadError() APT_OVERRIDE
   {
      return filefd->FileFdError("lzma_read: %s (%d)", _("Read error"), lzma->err);
   }
   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
   {
      ssize_t Res;
      lzma->stream.next_in = (uint8_t *)From;
      lzma->stream.avail_in = Size;
      lzma->stream.next_out = lzma->buffer;
      lzma->stream.avail_out = sizeof(lzma->buffer)/sizeof(lzma->buffer[0]);
      lzma->err = lzma_code(&lzma->stream, LZMA_RUN);
      if (lzma->err != LZMA_OK)
	 return -1;
      size_t const n = sizeof(lzma->buffer)/sizeof(lzma->buffer[0]) - lzma->stream.avail_out;
      size_t const m = (n == 0) ? 0 : fwrite(lzma->buffer, 1, n, lzma->file);
      if (m != n)
      {
	 Res = -1;
	 errno = 0;
      }
      else
      {
	 Res = Size - lzma->stream.avail_in;
	 if (Res == 0)
	 {
	    // lzma run was okay, but produced no output…
	    Res = -1;
	    errno = EINTR;
	 }
      }
      return Res;
   }
   virtual bool InternalWriteError() APT_OVERRIDE
   {
      return filefd->FileFdError("lzma_write: %s (%d)", _("Write error"), lzma->err);
   }
   virtual bool InternalStream() const APT_OVERRIDE { return true; }
   virtual bool InternalClose(std::string const &) APT_OVERRIDE
   {
      delete lzma;
      lzma = nullptr;
      return true;
   }

   explicit LzmaFileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd), lzma(nullptr) {}
   virtual ~LzmaFileFdPrivate() { InternalClose(""); }
#endif
};
									/*}}}*/
class APT_HIDDEN PipedFileFdPrivate: public FileFdPrivate				/*{{{*/
/* if we don't have a specific class dealing with library calls, we (un)compress
   by executing a specified binary and pipe in/out what we need */
{
public:
   virtual bool InternalOpen(int const, unsigned int const Mode) APT_OVERRIDE
   {
      // collect zombies here in case we reopen
      if (compressor_pid > 0)
	 ExecWait(compressor_pid, "FileFdCompressor", true);

      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
	 return filefd->FileFdError("ReadWrite mode is not supported for file %s", filefd->FileName.c_str());
      if (compressor.Binary == "false")
	 return filefd->FileFdError("libapt has inbuilt support for the %s compression,"
	       " but was forced to ignore it in favor of an external binary – which isn't installed.", compressor.Name.c_str());

      bool const Comp = (Mode & FileFd::WriteOnly) == FileFd::WriteOnly;
      if (Comp == false && filefd->iFd != -1)
      {
	 // Handle 'decompression' of empty files
	 struct stat Buf;
	 if (fstat(filefd->iFd, &Buf) != 0)
	    return filefd->FileFdErrno("fstat", "Could not stat fd %d for file %s", filefd->iFd, filefd->FileName.c_str());
	 if (Buf.st_size == 0 && S_ISFIFO(Buf.st_mode) == false)
	    return true;

	 // We don't need the file open - instead let the compressor open it
	 // as he properly knows better how to efficiently read from 'his' file
	 if (filefd->FileName.empty() == false)
	 {
	    close(filefd->iFd);
	    filefd->iFd = -1;
	 }
      }

      // Create a data pipe
      int Pipe[2] = {-1,-1};
      if (pipe(Pipe) != 0)
	 return filefd->FileFdErrno("pipe",_("Failed to create subprocess IPC"));
      for (int J = 0; J != 2; J++)
	 SetCloseExec(Pipe[J],true);

      compressed_fd = filefd->iFd;
      set_is_pipe(true);

      if (Comp == true)
	 filefd->iFd = Pipe[1];
      else
	 filefd->iFd = Pipe[0];

      // The child..
      compressor_pid = ExecFork();
      if (compressor_pid == 0)
      {
	 if (Comp == true)
	 {
	    dup2(compressed_fd,STDOUT_FILENO);
	    dup2(Pipe[0],STDIN_FILENO);
	 }
	 else
	 {
	    if (compressed_fd != -1)
	       dup2(compressed_fd,STDIN_FILENO);
	    dup2(Pipe[1],STDOUT_FILENO);
	 }

	 SetCloseExec(STDOUT_FILENO,false);
	 SetCloseExec(STDIN_FILENO,false);

	 std::vector<char const*> Args;
	 Args.push_back(compressor.Binary.c_str());
	 std::vector<std::string> const * const addArgs =
	    (Comp == true) ? &(compressor.CompressArgs) : &(compressor.UncompressArgs);
	 for (std::vector<std::string>::const_iterator a = addArgs->begin();
	       a != addArgs->end(); ++a)
	    Args.push_back(a->c_str());
	 if (Comp == false && filefd->FileName.empty() == false)
	 {
	    // commands not needing arguments, do not need to be told about using standard output
	    // in reality, only testcases with tools like cat, rev, rot13, … are able to trigger this
	    if (compressor.CompressArgs.empty() == false && compressor.UncompressArgs.empty() == false)
	       Args.push_back("--stdout");
	    if (filefd->TemporaryFileName.empty() == false)
	       Args.push_back(filefd->TemporaryFileName.c_str());
	    else
	       Args.push_back(filefd->FileName.c_str());
	 }
	 Args.push_back(NULL);

	 execvp(Args[0],(char **)&Args[0]);
	 cerr << _("Failed to exec compressor ") << Args[0] << endl;
	 _exit(100);
      }
      if (Comp == true)
	 close(Pipe[0]);
      else
	 close(Pipe[1]);

      return true;
   }
   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
   {
      return read(filefd->iFd, To, Size);
   }
   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
   {
      return write(filefd->iFd, From, Size);
   }
   virtual bool InternalClose(std::string const &) APT_OVERRIDE
   {
      bool Ret = true;
      if (filefd->iFd != -1)
      {
	 close(filefd->iFd);
	 filefd->iFd = -1;
      }
      if (compressor_pid > 0)
	 Ret &= ExecWait(compressor_pid, "FileFdCompressor", true);
      compressor_pid = -1;
      return Ret;
   }
   explicit PipedFileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd) {}
   virtual ~PipedFileFdPrivate() { InternalClose(""); }
};
									/*}}}*/
class APT_HIDDEN DirectFileFdPrivate: public FileFdPrivate				/*{{{*/
{
public:
   virtual bool InternalOpen(int const, unsigned int const) APT_OVERRIDE { return true; }
   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
   {
      return read(filefd->iFd, To, Size);
   }
   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
   {
      // files opened read+write are strange and only really "supported" for direct files
      if (buffer.size() != 0)
      {
	 lseek(filefd->iFd, -buffer.size(), SEEK_CUR);
	 buffer.reset();
      }
      return write(filefd->iFd, From, Size);
   }
   virtual bool InternalSeek(unsigned long long const To) APT_OVERRIDE
   {
      off_t const res = lseek(filefd->iFd, To, SEEK_SET);
      if (res != (off_t)To)
	 return filefd->FileFdError("Unable to seek to %llu", To);
      seekpos = To;
      buffer.reset();
      return true;
   }
   virtual bool InternalSkip(unsigned long long Over) APT_OVERRIDE
   {
      if (Over >= buffer.size())
      {
	 Over -= buffer.size();
	 buffer.reset();
      }
      else
      {
	 buffer.bufferstart += Over;
	 return true;
      }
      if (Over == 0)
	 return true;
      off_t const res = lseek(filefd->iFd, Over, SEEK_CUR);
      if (res < 0)
	 return filefd->FileFdError("Unable to seek ahead %llu",Over);
      seekpos = res;
      return true;
   }
   virtual bool InternalTruncate(unsigned long long const To) APT_OVERRIDE
   {
      if (buffer.size() != 0)
      {
	 unsigned long long const seekpos = lseek(filefd->iFd, 0, SEEK_CUR);
	 if ((seekpos - buffer.size()) >= To)
	    buffer.reset();
	 else if (seekpos >= To)
	    buffer.bufferend = (To - seekpos) + buffer.bufferstart;
	 else
	    buffer.reset();
      }
      if (ftruncate(filefd->iFd, To) != 0)
	 return filefd->FileFdError("Unable to truncate to %llu",To);
      return true;
   }
   virtual unsigned long long InternalTell() APT_OVERRIDE
   {
      return lseek(filefd->iFd,0,SEEK_CUR) - buffer.size();
   }
   virtual unsigned long long InternalSize() APT_OVERRIDE
   {
      return filefd->FileSize();
   }
   virtual bool InternalClose(std::string const &) APT_OVERRIDE { return true; }
   virtual bool InternalAlwaysAutoClose() const APT_OVERRIDE { return false; }

   explicit DirectFileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd) {}
   virtual ~DirectFileFdPrivate() { InternalClose(""); }
};
									/*}}}*/
// FileFd Constructors							/*{{{*/
FileFd::FileFd(std::string FileName,unsigned int const Mode,unsigned long AccessMode) : iFd(-1), Flags(0), d(NULL)
{
   Open(FileName,Mode, None, AccessMode);
}
FileFd::FileFd(std::string FileName,unsigned int const Mode, CompressMode Compress, unsigned long AccessMode) : iFd(-1), Flags(0), d(NULL)
{
   Open(FileName,Mode, Compress, AccessMode);
}
FileFd::FileFd() : iFd(-1), Flags(AutoClose), d(NULL) {}
FileFd::FileFd(int const Fd, unsigned int const Mode, CompressMode Compress) : iFd(-1), Flags(0), d(NULL)
{
   OpenDescriptor(Fd, Mode, Compress);
}
FileFd::FileFd(int const Fd, bool const AutoClose) : iFd(-1), Flags(0), d(NULL)
{
   OpenDescriptor(Fd, ReadWrite, None, AutoClose);
}
									/*}}}*/
// FileFd::Open - Open a file						/*{{{*/
// ---------------------------------------------------------------------
/* The most commonly used open mode combinations are given with Mode */
bool FileFd::Open(string FileName,unsigned int const Mode,CompressMode Compress, unsigned long const AccessMode)
{
   if (Mode == ReadOnlyGzip)
      return Open(FileName, ReadOnly, Gzip, AccessMode);

   if (Compress == Auto && (Mode & WriteOnly) == WriteOnly)
      return FileFdError("Autodetection on %s only works in ReadOnly openmode!", FileName.c_str());

   std::vector<APT::Configuration::Compressor> const compressors = APT::Configuration::getCompressors();
   std::vector<APT::Configuration::Compressor>::const_iterator compressor = compressors.begin();
   if (Compress == Auto)
   {
      for (; compressor != compressors.end(); ++compressor)
      {
	 std::string file = FileName + compressor->Extension;
	 if (FileExists(file) == false)
	    continue;
	 FileName = file;
	 break;
      }
   }
   else if (Compress == Extension)
   {
      std::string::size_type const found = FileName.find_last_of('.');
      std::string ext;
      if (found != std::string::npos)
      {
	 ext = FileName.substr(found);
	 if (ext == ".new" || ext == ".bak")
	 {
	    std::string::size_type const found2 = FileName.find_last_of('.', found - 1);
	    if (found2 != std::string::npos)
	       ext = FileName.substr(found2, found - found2);
	    else
	       ext.clear();
	 }
      }
      for (; compressor != compressors.end(); ++compressor)
	 if (ext == compressor->Extension)
	    break;
      // no matching extension - assume uncompressed (imagine files like 'example.org_Packages')
      if (compressor == compressors.end())
	 for (compressor = compressors.begin(); compressor != compressors.end(); ++compressor)
	    if (compressor->Name == ".")
	       break;
   }
   else
   {
      std::string name;
      switch (Compress)
      {
      case None: name = "."; break;
      case Gzip: name = "gzip"; break;
      case Bzip2: name = "bzip2"; break;
      case Lzma: name = "lzma"; break;
      case Xz: name = "xz"; break;
      case Lz4: name = "lz4"; break;
      case Auto:
      case Extension:
	 // Unreachable
	 return FileFdError("Opening File %s in None, Auto or Extension should be already handled?!?", FileName.c_str());
      }
      for (; compressor != compressors.end(); ++compressor)
	 if (compressor->Name == name)
	    break;
      if (compressor == compressors.end())
	 return FileFdError("Can't find a configured compressor %s for file %s", name.c_str(), FileName.c_str());
   }

   if (compressor == compressors.end())
      return FileFdError("Can't find a match for specified compressor mode for file %s", FileName.c_str());
   return Open(FileName, Mode, *compressor, AccessMode);
}
bool FileFd::Open(string FileName,unsigned int const Mode,APT::Configuration::Compressor const &compressor, unsigned long const AccessMode)
{
   Close();
   Flags = AutoClose;

   if ((Mode & WriteOnly) != WriteOnly && (Mode & (Atomic | Create | Empty | Exclusive)) != 0)
      return FileFdError("ReadOnly mode for %s doesn't accept additional flags!", FileName.c_str());
   if ((Mode & ReadWrite) == 0)
      return FileFdError("No openmode provided in FileFd::Open for %s", FileName.c_str());

   unsigned int OpenMode = Mode;
   if (FileName == "/dev/null")
      OpenMode = OpenMode & ~(Atomic | Exclusive | Create | Empty);

   if ((OpenMode & Atomic) == Atomic)
   {
      Flags |= Replace;
   }
   else if ((OpenMode & (Exclusive | Create)) == (Exclusive | Create))
   {
      // for atomic, this will be done by rename in Close()
      RemoveFile("FileFd::Open", FileName);
   }
   if ((OpenMode & Empty) == Empty)
   {
      struct stat Buf;
      if (lstat(FileName.c_str(),&Buf) == 0 && S_ISLNK(Buf.st_mode))
	 RemoveFile("FileFd::Open", FileName);
   }

   int fileflags = 0;
   #define if_FLAGGED_SET(FLAG, MODE) if ((OpenMode & FLAG) == FLAG) fileflags |= MODE
   if_FLAGGED_SET(ReadWrite, O_RDWR);
   else if_FLAGGED_SET(ReadOnly, O_RDONLY);
   else if_FLAGGED_SET(WriteOnly, O_WRONLY);

   if_FLAGGED_SET(Create, O_CREAT);
   if_FLAGGED_SET(Empty, O_TRUNC);
   if_FLAGGED_SET(Exclusive, O_EXCL);
   #undef if_FLAGGED_SET

   if ((OpenMode & Atomic) == Atomic)
   {
      char *name = strdup((FileName + ".XXXXXX").c_str());

      if((iFd = mkstemp(name)) == -1)
      {
          free(name);
          return FileFdErrno("mkstemp", "Could not create temporary file for %s", FileName.c_str());
      }

      TemporaryFileName = string(name);
      free(name);

      // umask() will always set the umask and return the previous value, so
      // we first set the umask and then reset it to the old value
      mode_t const CurrentUmask = umask(0);
      umask(CurrentUmask);
      // calculate the actual file permissions (just like open/creat)
      mode_t const FilePermissions = (AccessMode & ~CurrentUmask);

      if(fchmod(iFd, FilePermissions) == -1)
          return FileFdErrno("fchmod", "Could not change permissions for temporary file %s", TemporaryFileName.c_str());
   }
   else
      iFd = open(FileName.c_str(), fileflags, AccessMode);

   this->FileName = FileName;
   if (iFd == -1 || OpenInternDescriptor(OpenMode, compressor) == false)
   {
      if (iFd != -1)
      {
	 close (iFd);
	 iFd = -1;
      }
      return FileFdErrno("open",_("Could not open file %s"), FileName.c_str());
   }

   SetCloseExec(iFd,true);
   return true;
}
									/*}}}*/
// FileFd::OpenDescriptor - Open a filedescriptor			/*{{{*/
bool FileFd::OpenDescriptor(int Fd, unsigned int const Mode, CompressMode Compress, bool AutoClose)
{
   std::vector<APT::Configuration::Compressor> const compressors = APT::Configuration::getCompressors();
   std::vector<APT::Configuration::Compressor>::const_iterator compressor = compressors.begin();
   std::string name;

   // compat with the old API
   if (Mode == ReadOnlyGzip && Compress == None)
      Compress = Gzip;

   switch (Compress)
   {
   case None: name = "."; break;
   case Gzip: name = "gzip"; break;
   case Bzip2: name = "bzip2"; break;
   case Lzma: name = "lzma"; break;
   case Xz: name = "xz"; break;
   case Lz4: name = "lz4"; break;
   case Auto:
   case Extension:
      if (AutoClose == true && Fd != -1)
	 close(Fd);
      return FileFdError("Opening Fd %d in Auto or Extension compression mode is not supported", Fd);
   }
   for (; compressor != compressors.end(); ++compressor)
      if (compressor->Name == name)
	 break;
   if (compressor == compressors.end())
   {
      if (AutoClose == true && Fd != -1)
	 close(Fd);
      return FileFdError("Can't find a configured compressor %s for file %s", name.c_str(), FileName.c_str());
   }
   return OpenDescriptor(Fd, Mode, *compressor, AutoClose);
}
bool FileFd::OpenDescriptor(int Fd, unsigned int const Mode, APT::Configuration::Compressor const &compressor, bool AutoClose)
{
   Close();
   Flags = (AutoClose) ? FileFd::AutoClose : 0;
   iFd = Fd;
   this->FileName = "";
   if (OpenInternDescriptor(Mode, compressor) == false)
   {
      if (iFd != -1 && (
	(Flags & Compressed) == Compressed ||
	AutoClose == true))
      {
	 close (iFd);
	 iFd = -1;
      }
      return FileFdError(_("Could not open file descriptor %d"), Fd);
   }
   return true;
}
bool FileFd::OpenInternDescriptor(unsigned int const Mode, APT::Configuration::Compressor const &compressor)
{
   if (iFd == -1)
      return false;

   if (d != nullptr)
      d->InternalClose(FileName);

   if (d == nullptr)
   {
      if (false)
	 /* dummy so that the rest can be 'else if's */;
#define APT_COMPRESS_INIT(NAME, CONSTRUCTOR) \
      else if (compressor.Name == NAME) \
	 d = new CONSTRUCTOR(this)
#ifdef HAVE_ZLIB
      APT_COMPRESS_INIT("gzip", GzipFileFdPrivate);
#endif
#ifdef HAVE_BZ2
      APT_COMPRESS_INIT("bzip2", Bz2FileFdPrivate);
#endif
#ifdef HAVE_LZMA
      APT_COMPRESS_INIT("xz", LzmaFileFdPrivate);
      APT_COMPRESS_INIT("lzma", LzmaFileFdPrivate);
#endif
#ifdef HAVE_LZ4
      APT_COMPRESS_INIT("lz4", Lz4FileFdPrivate);
#endif
#undef APT_COMPRESS_INIT
      else if (compressor.Name == "." || compressor.Binary.empty() == true)
	 d = new DirectFileFdPrivate(this);
      else
	 d = new PipedFileFdPrivate(this);

      if (Mode & BufferedWrite)
	 d = new BufferedWriteFileFdPrivate(d);

      d->set_openmode(Mode);
      d->set_compressor(compressor);
      if ((Flags & AutoClose) != AutoClose && d->InternalAlwaysAutoClose())
      {
	 // Need to duplicate fd here or gz/bz2 close for cleanup will close the fd as well
	 int const internFd = dup(iFd);
	 if (internFd == -1)
	    return FileFdErrno("OpenInternDescriptor", _("Could not open file descriptor %d"), iFd);
	 iFd = internFd;
      }
   }
   return d->InternalOpen(iFd, Mode);
}
									/*}}}*/
// FileFd::~File - Closes the file					/*{{{*/
// ---------------------------------------------------------------------
/* If the proper modes are selected then we close the Fd and possibly
   unlink the file on error. */
FileFd::~FileFd()
{
   Close();
   if (d != NULL)
      d->InternalClose(FileName);
   delete d;
   d = NULL;
}
									/*}}}*/
// FileFd::Read - Read a bit of the file				/*{{{*/
// ---------------------------------------------------------------------
/* We are careful to handle interruption by a signal while reading
   gracefully. */
bool FileFd::Read(void *To,unsigned long long Size,unsigned long long *Actual)
{
   if (d == nullptr || Failed())
      return false;
   ssize_t Res = 1;
   errno = 0;
   if (Actual != 0)
      *Actual = 0;
   *((char *)To) = '\0';
   while (Res > 0 && Size > 0)
   {
      Res = d->InternalRead(To, Size);

      if (Res < 0)
      {
	 if (errno == EINTR)
	 {
	    // trick the while-loop into running again
	    Res = 1;
	    errno = 0;
	    continue;
	 }
	 return d->InternalReadError();
      }
      
      To = (char *)To + Res;
      Size -= Res;
      if (d != NULL)
	 d->set_seekpos(d->get_seekpos() + Res);
      if (Actual != 0)
	 *Actual += Res;
   }
   
   if (Size == 0)
      return true;
   
   // Eof handling
   if (Actual != 0)
   {
      Flags |= HitEof;
      return true;
   }

   return FileFdError(_("read, still have %llu to read but none left"), Size);
}
bool FileFd::Read(int const Fd, void *To, unsigned long long Size, unsigned long long * const Actual)
{
   ssize_t Res = 1;
   errno = 0;
   if (Actual != nullptr)
      *Actual = 0;
   *static_cast<char *>(To) = '\0';
   while (Res > 0 && Size > 0)
   {
      Res = read(Fd, To, Size);
      if (Res < 0)
      {
	 if (errno == EINTR)
	 {
	    Res = 1;
	    errno = 0;
	    continue;
	 }
	 return _error->Errno("read", _("Read error"));
      }
      To = static_cast<char *>(To) + Res;
      Size -= Res;
      if (Actual != 0)
	 *Actual += Res;
   }
   if (Size == 0)
      return true;
   if (Actual != nullptr)
      return true;
   return _error->Error(_("read, still have %llu to read but none left"), Size);
}
									/*}}}*/
// FileFd::ReadLine - Read a complete line from the file		/*{{{*/
// ---------------------------------------------------------------------
/* Beware: This method can be quite slow for big buffers on UNcompressed
   files because of the naive implementation! */
char* FileFd::ReadLine(char *To, unsigned long long const Size)
{
   *To = '\0';
   if (d == nullptr || Failed())
      return nullptr;
   return d->InternalReadLine(To, Size);
}
									/*}}}*/
// FileFd::Flush - Flush the file  					/*{{{*/
bool FileFd::Flush()
{
   if (Failed())
      return false;
   if (d == nullptr)
      return true;

   return d->InternalFlush();
}
									/*}}}*/
// FileFd::Write - Write to the file					/*{{{*/
bool FileFd::Write(const void *From,unsigned long long Size)
{
   if (d == nullptr || Failed())
      return false;
   ssize_t Res = 1;
   errno = 0;
   while (Res > 0 && Size > 0)
   {
      Res = d->InternalWrite(From, Size);

      if (Res < 0)
      {
	 if (errno == EINTR)
	 {
	    // trick the while-loop into running again
	    Res = 1;
	    errno = 0;
	    continue;
	 }
	 return d->InternalWriteError();
      }

      From = (char const *)From + Res;
      Size -= Res;
      if (d != NULL)
	 d->set_seekpos(d->get_seekpos() + Res);
   }

   if (Size == 0)
      return true;

   return FileFdError(_("write, still have %llu to write but couldn't"), Size);
}
bool FileFd::Write(int Fd, const void *From, unsigned long long Size)
{
   ssize_t Res = 1;
   errno = 0;
   while (Res > 0 && Size > 0)
   {
      Res = write(Fd,From,Size);
      if (Res < 0 && errno == EINTR)
	 continue;
      if (Res < 0)
	 return _error->Errno("write",_("Write error"));

      From = (char const *)From + Res;
      Size -= Res;
   }

   if (Size == 0)
      return true;

   return _error->Error(_("write, still have %llu to write but couldn't"), Size);
}
									/*}}}*/
// FileFd::Seek - Seek in the file					/*{{{*/
bool FileFd::Seek(unsigned long long To)
{
   if (d == nullptr || Failed())
      return false;
   Flags &= ~HitEof;
   return d->InternalSeek(To);
}
									/*}}}*/
// FileFd::Skip - Skip over data in the file				/*{{{*/
bool FileFd::Skip(unsigned long long Over)
{
   if (d == nullptr || Failed())
      return false;
   return d->InternalSkip(Over);
}
									/*}}}*/
// FileFd::Truncate - Truncate the file					/*{{{*/
bool FileFd::Truncate(unsigned long long To)
{
   if (d == nullptr || Failed())
      return false;
   // truncating /dev/null is always successful - as we get an error otherwise
   if (To == 0 && FileName == "/dev/null")
      return true;
   return d->InternalTruncate(To);
}
									/*}}}*/
// FileFd::Tell - Current seek position					/*{{{*/
// ---------------------------------------------------------------------
/* */
unsigned long long FileFd::Tell()
{
   if (d == nullptr || Failed())
      return false;
   off_t const Res = d->InternalTell();
   if (Res == (off_t)-1)
      FileFdErrno("lseek","Failed to determine the current file position");
   d->set_seekpos(Res);
   return Res;
}
									/*}}}*/
static bool StatFileFd(char const * const msg, int const iFd, std::string const &FileName, struct stat &Buf, FileFdPrivate * const d) /*{{{*/
{
   bool ispipe = (d != NULL && d->get_is_pipe() == true);
   if (ispipe == false)
   {
      if (fstat(iFd,&Buf) != 0)
	 // higher-level code will generate more meaningful messages,
	 // even translated this would be meaningless for users
	 return _error->Errno("fstat", "Unable to determine %s for fd %i", msg, iFd);
      if (FileName.empty() == false)
	 ispipe = S_ISFIFO(Buf.st_mode);
   }

   // for compressor pipes st_size is undefined and at 'best' zero
   if (ispipe == true)
   {
      // we set it here, too, as we get the info here for free
      // in theory the Open-methods should take care of it already
      if (d != NULL)
	 d->set_is_pipe(true);
      if (stat(FileName.c_str(), &Buf) != 0)
	 return _error->Errno("fstat", "Unable to determine %s for file %s", msg, FileName.c_str());
   }
   return true;
}
									/*}}}*/
// FileFd::FileSize - Return the size of the file			/*{{{*/
unsigned long long FileFd::FileSize()
{
   struct stat Buf;
   if (StatFileFd("file size", iFd, FileName, Buf, d) == false)
   {
      Flags |= Fail;
      return 0;
   }
   return Buf.st_size;
}
									/*}}}*/
// FileFd::ModificationTime - Return the time of last touch		/*{{{*/
time_t FileFd::ModificationTime()
{
   struct stat Buf;
   if (StatFileFd("modification time", iFd, FileName, Buf, d) == false)
   {
      Flags |= Fail;
      return 0;
   }
   return Buf.st_mtime;
}
									/*}}}*/
// FileFd::Size - Return the size of the content in the file		/*{{{*/
unsigned long long FileFd::Size()
{
   if (d == nullptr)
      return 0;
   return d->InternalSize();
}
									/*}}}*/
// FileFd::Close - Close the file if the close flag is set		/*{{{*/
// ---------------------------------------------------------------------
/* */
bool FileFd::Close()
{
   if (Failed() == false && Flush() == false)
      return false;
   if (iFd == -1)
      return true;

   bool Res = true;
   if ((Flags & AutoClose) == AutoClose)
   {
      if ((Flags & Compressed) != Compressed && iFd > 0 && close(iFd) != 0)
	 Res &= _error->Errno("close",_("Problem closing the file %s"), FileName.c_str());
   }

   if (d != NULL)
   {
      Res &= d->InternalClose(FileName);
      delete d;
      d = NULL;
   }

   if ((Flags & Replace) == Replace) {
      if (Failed() == false && rename(TemporaryFileName.c_str(), FileName.c_str()) != 0)
	 Res &= _error->Errno("rename",_("Problem renaming the file %s to %s"), TemporaryFileName.c_str(), FileName.c_str());

      FileName = TemporaryFileName; // for the unlink() below.
      TemporaryFileName.clear();
   }

   iFd = -1;

   if ((Flags & Fail) == Fail && (Flags & DelOnFail) == DelOnFail &&
       FileName.empty() == false)
      Res &= RemoveFile("FileFd::Close", FileName);

   if (Res == false)
      Flags |= Fail;
   return Res;
}
									/*}}}*/
// FileFd::Sync - Sync the file						/*{{{*/
// ---------------------------------------------------------------------
/* */
bool FileFd::Sync()
{
   if (fsync(iFd) != 0)
      return FileFdErrno("sync",_("Problem syncing the file"));
   return true;
}
									/*}}}*/
// FileFd::FileFdErrno - set Fail and call _error->Errno		*{{{*/
bool FileFd::FileFdErrno(const char *Function, const char *Description,...)
{
   Flags |= Fail;
   va_list args;
   size_t msgSize = 400;
   int const errsv = errno;
   bool retry;
   do {
      va_start(args,Description);
      retry = _error->InsertErrno(GlobalError::ERROR, Function, Description, args, errsv, msgSize);
      va_end(args);
   } while (retry);
   return false;
}
									/*}}}*/
// FileFd::FileFdError - set Fail and call _error->Error		*{{{*/
bool FileFd::FileFdError(const char *Description,...) {
   Flags |= Fail;
   va_list args;
   size_t msgSize = 400;
   bool retry;
   do {
      va_start(args,Description);
      retry = _error->Insert(GlobalError::ERROR, Description, args, msgSize);
      va_end(args);
   } while (retry);
   return false;
}
									/*}}}*/
gzFile FileFd::gzFd() {							/*{{{*/
#ifdef HAVE_ZLIB
   GzipFileFdPrivate * const gzipd = dynamic_cast<GzipFileFdPrivate*>(d);
   if (gzipd == nullptr)
      return nullptr;
   else
      return gzipd->gz;
#else
   return nullptr;
#endif
}
									/*}}}*/

// Glob - wrapper around "glob()"					/*{{{*/
std::vector<std::string> Glob(std::string const &pattern, int flags)
{
   std::vector<std::string> result;
   glob_t globbuf;
   int glob_res;
   unsigned int i;

   glob_res = glob(pattern.c_str(),  flags, NULL, &globbuf);

   if (glob_res != 0)
   {
      if(glob_res != GLOB_NOMATCH) {
         _error->Errno("glob", "Problem with glob");
         return result;
      }
   }

   // append results
   for(i=0;i<globbuf.gl_pathc;i++)
      result.push_back(string(globbuf.gl_pathv[i]));

   globfree(&globbuf);
   return result;
}
									/*}}}*/
static std::string APT_NONNULL(1) GetTempDirEnv(char const * const env)	/*{{{*/
{
   const char *tmpdir = getenv(env);

#ifdef P_tmpdir
   if (!tmpdir)
      tmpdir = P_tmpdir;
#endif

   struct stat st;
   if (!tmpdir || strlen(tmpdir) == 0 || // tmpdir is set
	 stat(tmpdir, &st) != 0 || (st.st_mode & S_IFDIR) == 0) // exists and is directory
      tmpdir = "/tmp";
   else if (geteuid() != 0 && // root can do everything anyway
	 faccessat(-1, tmpdir, R_OK | W_OK | X_OK, AT_EACCESS | AT_SYMLINK_NOFOLLOW) != 0) // current user has rwx access to directory
      tmpdir = "/tmp";

   return string(tmpdir);
}
									/*}}}*/
std::string GetTempDir()						/*{{{*/
{
   return GetTempDirEnv("TMPDIR");
}
std::string GetTempDir(std::string const &User)
{
   // no need/possibility to drop privs
   if(getuid() != 0 || User.empty() || User == "root")
      return GetTempDir();

   struct passwd const * const pw = getpwnam(User.c_str());
   if (pw == NULL)
      return GetTempDir();

   gid_t const old_euid = geteuid();
   gid_t const old_egid = getegid();
   if (setegid(pw->pw_gid) != 0)
      _error->Errno("setegid", "setegid %u failed", pw->pw_gid);
   if (seteuid(pw->pw_uid) != 0)
      _error->Errno("seteuid", "seteuid %u failed", pw->pw_uid);

   std::string const tmp = GetTempDir();

   if (seteuid(old_euid) != 0)
      _error->Errno("seteuid", "seteuid %u failed", old_euid);
   if (setegid(old_egid) != 0)
      _error->Errno("setegid", "setegid %u failed", old_egid);

   return tmp;
}
									/*}}}*/
FileFd* GetTempFile(std::string const &Prefix, bool ImmediateUnlink, FileFd * const TmpFd)	/*{{{*/
{
   char fn[512];
   FileFd * const Fd = TmpFd == NULL ? new FileFd() : TmpFd;

   std::string const tempdir = GetTempDir();
   snprintf(fn, sizeof(fn), "%s/%s.XXXXXX",
            tempdir.c_str(), Prefix.c_str());
   int const fd = mkstemp(fn);
   if(ImmediateUnlink)
      unlink(fn);
   if (fd < 0)
   {
      _error->Errno("GetTempFile",_("Unable to mkstemp %s"), fn);
      return NULL;
   }
   if (!Fd->OpenDescriptor(fd, FileFd::ReadWrite, FileFd::None, true))
   {
      _error->Errno("GetTempFile",_("Unable to write to %s"),fn);
      return NULL;
   }
   return Fd;
}
									/*}}}*/
bool Rename(std::string From, std::string To)				/*{{{*/
{
   if (rename(From.c_str(),To.c_str()) != 0)
   {
      _error->Error(_("rename failed, %s (%s -> %s)."),strerror(errno),
                    From.c_str(),To.c_str());
      return false;
   }
   return true;
}
									/*}}}*/
bool Popen(const char* Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode)/*{{{*/
{
   return Popen(Args, Fd, Child, Mode, true);
}
									/*}}}*/
bool Popen(const char* Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode, bool CaptureStderr)/*{{{*/
{
   int fd;
   if (Mode != FileFd::ReadOnly && Mode != FileFd::WriteOnly)
      return _error->Error("Popen supports ReadOnly (x)or WriteOnly mode only");

   int Pipe[2] = {-1, -1};
   if(pipe(Pipe) != 0)
      return _error->Errno("pipe", _("Failed to create subprocess IPC"));

   std::set<int> keep_fds;
   keep_fds.insert(Pipe[0]);
   keep_fds.insert(Pipe[1]);
   Child = ExecFork(keep_fds);
   if(Child < 0)
      return _error->Errno("fork", "Failed to fork");
   if(Child == 0)
   {
      if(Mode == FileFd::ReadOnly)
      {
         close(Pipe[0]);
         fd = Pipe[1];
      }
      else if(Mode == FileFd::WriteOnly)
      {
         close(Pipe[1]);
         fd = Pipe[0];
      }

      if(Mode == FileFd::ReadOnly)
      {
         dup2(fd, 1);
	 if (CaptureStderr == true)
	    dup2(fd, 2);
      } else if(Mode == FileFd::WriteOnly)
         dup2(fd, 0);

      execv(Args[0], (char**)Args);
      _exit(100);
   }
   if(Mode == FileFd::ReadOnly)
   {
      close(Pipe[1]);
      fd = Pipe[0];
   }
   else if(Mode == FileFd::WriteOnly)
   {
      close(Pipe[0]);
      fd = Pipe[1];
   }
   else
      return _error->Error("Popen supports ReadOnly (x)or WriteOnly mode only");
   Fd.OpenDescriptor(fd, Mode, FileFd::None, true);

   return true;
}
									/*}}}*/
bool DropPrivileges()							/*{{{*/
{
   if(_config->FindB("Debug::NoDropPrivs", false) == true)
      return true;

#if __gnu_linux__
#if defined(PR_SET_NO_NEW_PRIVS) && ( PR_SET_NO_NEW_PRIVS != 38 )
#error "PR_SET_NO_NEW_PRIVS is defined, but with a different value than expected!"
#endif
   // see prctl(2), needs linux3.5 at runtime - magic constant to avoid it at buildtime
   int ret = prctl(38, 1, 0, 0, 0);
   // ignore EINVAL - kernel is too old to understand the option
   if(ret < 0 && errno != EINVAL)
      _error->Warning("PR_SET_NO_NEW_PRIVS failed with %i", ret);
#endif

   // empty setting disables privilege dropping - this also ensures
   // backward compatibility, see bug #764506
   const std::string toUser = _config->Find("APT::Sandbox::User");
   if (toUser.empty() || toUser == "root")
      return true;

   // a lot can go wrong trying to drop privileges completely,
   // so ideally we would like to verify that we have done it –
   // but the verify asks for too much in case of fakeroot (and alike)
   // [Specific checks can be overridden with dedicated options]
   bool const VerifySandboxing = _config->FindB("APT::Sandbox::Verify", false);

   // uid will be 0 in the end, but gid might be different anyway
   uid_t const old_uid = getuid();
   gid_t const old_gid = getgid();

   if (old_uid != 0)
      return true;

   struct passwd *pw = getpwnam(toUser.c_str());
   if (pw == NULL)
      return _error->Error("No user %s, can not drop rights", toUser.c_str());

   // Do not change the order here, it might break things
   // Get rid of all our supplementary groups first
   if (setgroups(1, &pw->pw_gid))
      return _error->Errno("setgroups", "Failed to setgroups");

   // Now change the group ids to the new user
#ifdef HAVE_SETRESGID
   if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0)
      return _error->Errno("setresgid", "Failed to set new group ids");
#else
   if (setegid(pw->pw_gid) != 0)
      return _error->Errno("setegid", "Failed to setegid");

   if (setgid(pw->pw_gid) != 0)
      return _error->Errno("setgid", "Failed to setgid");
#endif

   // Change the user ids to the new user
#ifdef HAVE_SETRESUID
   if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0)
      return _error->Errno("setresuid", "Failed to set new user ids");
#else
   if (setuid(pw->pw_uid) != 0)
      return _error->Errno("setuid", "Failed to setuid");
   if (seteuid(pw->pw_uid) != 0)
      return _error->Errno("seteuid", "Failed to seteuid");
#endif

   // disabled by default as fakeroot doesn't implement getgroups currently (#806521)
   if (VerifySandboxing == true || _config->FindB("APT::Sandbox::Verify::Groups", false) == true)
   {
      // Verify that the user isn't still in any supplementary groups
      long const ngroups_max = sysconf(_SC_NGROUPS_MAX);
      std::unique_ptr<gid_t[]> gidlist(new gid_t[ngroups_max]);
      if (unlikely(gidlist == NULL))
	 return _error->Error("Allocation of a list of size %lu for getgroups failed", ngroups_max);
      ssize_t gidlist_nr;
      if ((gidlist_nr = getgroups(ngroups_max, gidlist.get())) < 0)
	 return _error->Errno("getgroups", "Could not get new groups (%lu)", ngroups_max);
      for (ssize_t i = 0; i < gidlist_nr; ++i)
	 if (gidlist[i] != pw->pw_gid)
	    return _error->Error("Could not switch group, user %s is still in group %d", toUser.c_str(), gidlist[i]);
   }

   // enabled by default as all fakeroot-lookalikes should fake that accordingly
   if (VerifySandboxing == true || _config->FindB("APT::Sandbox::Verify::IDs", true) == true)
   {
      // Verify that gid, egid, uid, and euid changed
      if (getgid() != pw->pw_gid)
	 return _error->Error("Could not switch group");
      if (getegid() != pw->pw_gid)
	 return _error->Error("Could not switch effective group");
      if (getuid() != pw->pw_uid)
	 return _error->Error("Could not switch user");
      if (geteuid() != pw->pw_uid)
	 return _error->Error("Could not switch effective user");

#ifdef HAVE_GETRESUID
      // verify that the saved set-user-id was changed as well
      uid_t ruid = 0;
      uid_t euid = 0;
      uid_t suid = 0;
      if (getresuid(&ruid, &euid, &suid))
	 return _error->Errno("getresuid", "Could not get saved set-user-ID");
      if (suid != pw->pw_uid)
	 return _error->Error("Could not switch saved set-user-ID");
#endif

#ifdef HAVE_GETRESGID
      // verify that the saved set-group-id was changed as well
      gid_t rgid = 0;
      gid_t egid = 0;
      gid_t sgid = 0;
      if (getresgid(&rgid, &egid, &sgid))
	 return _error->Errno("getresuid", "Could not get saved set-group-ID");
      if (sgid != pw->pw_gid)
	 return _error->Error("Could not switch saved set-group-ID");
#endif
   }

   // disabled as fakeroot doesn't forbid (by design) (re)gaining root from unprivileged
   if (VerifySandboxing == true || _config->FindB("APT::Sandbox::Verify::Regain", false) == true)
   {
      // Check that uid and gid changes do not work anymore
      if (pw->pw_gid != old_gid && (setgid(old_gid) != -1 || setegid(old_gid) != -1))
	 return _error->Error("Could restore a gid to root, privilege dropping did not work");

      if (pw->pw_uid != old_uid && (setuid(old_uid) != -1 || seteuid(old_uid) != -1))
	 return _error->Error("Could restore a uid to root, privilege dropping did not work");
   }

   if (_config->FindB("APT::Sandbox::ResetEnvironment", true))
   {
      setenv("HOME", pw->pw_dir, 1);
      setenv("USER", pw->pw_name, 1);
      setenv("USERNAME", pw->pw_name, 1);
      setenv("LOGNAME", pw->pw_name, 1);
      auto const shell = flNotDir(pw->pw_shell);
      if (shell == "false" || shell == "nologin")
	 setenv("SHELL", "/bin/sh", 1);
      else
	 setenv("SHELL", pw->pw_shell, 1);
      auto const apt_setenv_tmp = [](char const * const env) {
	 auto const tmpdir = getenv(env);
	 if (tmpdir != nullptr)
	 {
	    auto const ourtmpdir = GetTempDirEnv(env);
	    if (ourtmpdir != tmpdir)
	       setenv(env, ourtmpdir.c_str(), 1);
	 }
      };
      apt_setenv_tmp("TMPDIR");
      apt_setenv_tmp("TEMPDIR");
      apt_setenv_tmp("TMP");
      apt_setenv_tmp("TEMP");
   }

   return true;
}
									/*}}}*/